44th Annual Meeting – General Session, May 15, “Preserving Trauma: Treatment Challenges at the 9/11 Memorial Museum” by John Childs and Maureen Merrigan

John Childs presented the treatment and installation challenges the conservation team faced at the 9/11 Memorial museum.
After 9/11, spontaneous memorials appeared, and the 9/11 Memorial Museum became the permanent memorial for this tragic event. It created a need to save and preserve physical evidence of the attacks, ranging from bits of paper to enormous steel girder and fire engines, not because of what it was but how it demonstrated in a physical way the trauma of that day. As conservators, we recognize where value lies in making treatment decisions, but poor condition itself is valued for the 9/11 Memorial Museum. Three treatments that posed philosophical challenges were explored in this talk.
The first was a Warner Bros. sign, which was saved from the store on the concourse level of the World Trade Center by some workers who found the material evocative. The object included letters as well as portions of the wall it was installed on. The question became how much of the sign to include in exhibition: the whole thing? The letters, cement tile, and mortar? Just the letters? Childs questioned whether this discussion was legitimate. Museums don’t usually select portions of an object but when extracting bits of wreckage, where are the boundaries between one object from another? There were so many layers that they distracted from the letters, so the decision was made to saw off wall board from the letters because that is where the value lies. It was then affixed to aluminum honeycomb and rendered legible as an object but also preserved the trauma it suffered. It takes its place among evocative objects from the site.
The second treatment involved the B2 parking level wall from the garage. The preservation of trauma is the primary conservation goal: the preservation of trauma of specific events, 9/11, but also of February 21, 1993, the truck bomb in the garage of the World Trade Center. Part of the B2 parking level wall, complete with scorch marks, was covered, wrapped, and transported to museum. It arrived during construction of the building and protections against flooding were not in place at this time. Hurricane Sandy flooded the area and seven feet of water went into the museum site, submerging large objects under water. It took five days to pump the water out and clean the objects. Vehicles or steel were primarily the large objects and medium pressure steam was used to clean these objects. The B2 slab was now covered with a layer of silt on its surface, on top of the soot from 9/11. The decision was made to completely remove evidence of Sandy, though Sandy was now another trauma suffered in NY. The value of the collection lies in its history and this would be hiding that history, but the mission of the museum was not to preserve the memory of Sandy. They had to remove the trauma of Sandy while preserving trauma of 9/11. They delayed treatment and found that as the silt dried, it could be brushed off without disturbing the 9/11 soot underneath. They waited until it was installed vertically in the exhibition and brushed the surface into a HEPA vacuum, revealing the soot.
Dust was an enormously significant part of the story, including silica, asbestos, and man-made vitreous fibers, creating a decidedly unhealthy environment. This really amounted to human remains. Dust was all that people had left of loved ones. Dust had a unique place in that story, as both a lethal and sacred substance. Childs stated that there is a palpable and justifiable fear of it in NY still today. Dust was donated to the museum, and one of the most significant donations is a display of Chelsea Jeans, a store on Broadway a couple of blocks from the site. The owner found the store under a thick layer of dust and left part of the store undisturbed, sealed behind glass to protect customers. He donated the storefront to the New York Historical Society, who used asbestos mitigation to deinstall and move it to NYHS. It was put on display in 2006 in a specially designed case and then donated to the 9/11 museum. To install it, the museum had to hire an environmental mitigation company to create an asbestos containment chamber in the galleries. Those working on the display took a course on asbestos training, had medical tests and a respirator fit testing. The containment chamber consisted of crates for objects, crates for glass sealing case, entry chamber (air lock), and a shower for decontamination after exiting enclosure. They all wore respirators and disposable coveralls. Given the situation, they had to make installation decisions as they were working, and they had a window so curators could be involved from the outside. The case was installed in a way that curators thought would best represent the original display. Glazers were installed and sealed the glass. Many people not used to standard museum procedures were very involved in this process, making cooperation and compromise absolutely necessary. This exhibition combines, in one setting, all of the disparate meanings of dust on 9/11 and is in the section on response and recovery of the museum.
For the 9/11 museum, damage and destruction is the story. For conservation, it is critical to appropriately save the evidence of damage that will tell the story effectively. Childs expressed how it can be emotionally charged with horror, sadness, and loss. The museum and experience have a profound meaning for a huge number of people, and Childs ended his talk by expressing what an absolute honor it was to participate.

44th Annual Meeting – General Session, May 15, “When disaster mitigation is a priority: Evidence from risk analysis of rare events” by Irene Karsten and Stefan Michalski

In this talk, Irene Karsten presented a method that CCI has established to quantitatively evaluate risk assessment for an institution. CCI has been using this method, called the ABC method, to conduct risk assessment for heritage institutions. The probability of a certain incident is estimated by answering the following questions:

  1. How often will the event occur?
  2. How much value will be lost?
  3. How much of the heritage asset will be affected?

A score of 5 points is generated for A, B, and C, for a total magnitude risk out of 15 points. A total of 5 points or lower is considered negligible risk and 15 points is catastrophic and unacceptable.

Score Risk Loss to collection
5 or lower Negligible  
9 or lower Medium to negligible Damage takes millennia. May agree that level of care is adequate and improvements possible but wait till higher risks are reduced.
10-11 Medium – high Maybe negotiable. Standard of care may be okay but improvements highly recommended
12-13 High Lost in 100 years, may be unacceptable
15 Catastrophic Unacceptable. All value lost in decades. Such risks are rare.

 
In this talk, Karsten is paying particularly attention to level 10-13 risks. Also, this is a logarithmic scale, which allows the authors to graph a lot of risks on each graph and compare them easily. Karsten went through a number of examples, including two historic houses, art gallery, provincial archives, and science and technology museum, highlighting the various risks and how they were evaluated. For all five institutions, disaster risks in high or extreme categories were fire. CCI did not just assess the risks, but also looked at mitigation of risk. For fire, CCI recommends an automatic fire suppression system. This does not eliminate fire risk but substantially reduces the risk of spread. In terms of cost-effectiveness, options that reduce large risks tend to have a better cost-effectiveness, too. When assessing if your collection is at a serious risk of loss, it has to impact storage.
 
Karsten then went through five types of weather disasters and explained how an institution would be assessed to be at an extreme or high risk for that threat.
For a flood, an institution is at extreme risk if storage is below flood grade or even below grade near the old water main or faulty storm sewers. An institution is at high risk if it is on grade on a flood plain or below grade.
For a fire, an institution is at extreme or high risk if it is a combustible building structure, there is lack of compartmentation, the region is at risk of wild fire, or there is a lack of automatic fire suppression. 1 in 5 fires is expected to spread to the whole structure.
For an earthquake, an institution is at extreme risk if the building is lacking seismic protection and there is a risk of violent earthquakes (7 or higher on the Richter scale). An institution is at high risk if storage is lacking seismic protection and there is a risk of very strong to violent earthquakes (6.5 or higher on the Richter scale).
For a tornado, an extreme risk is EF4 or EF5 tornados in US and high risk of EF4-5 in Canada, depending on the frequency of tornados in the area.
For a hurricane, an extreme risk is if the building is in a region at risk of major hurricanes (category 3-5) and the building is not designed to resist high winds. In Canada, only category 2 hurricanes really occur, and the damage is rarely extensive to be high or extreme risk.

42nd Annual Meeting – Book and Paper Group, May 31, “Indian Coloured Drawings: Modern Repair Techniques for an Album of 19th Century Paintings on Mica by Sarah Reidell”

In this talk, Sarah Reidell gave a detailed description of her treatment of an album of 19th century paintings on mica from the New York Public Library collection.
Her treatment steps included:

  1. Hows and whys – background research
  2. Stabilize – consolidation
  3. Digitize – high quality files
  4. Accessorize – new archival mats and housings
  5. Publicize – increase awareness to researchers/public/staff

The albums had red buckram, generally indicating NYPL bindery work, and perhaps also associated with the WPA. There were two volumes of albums, Volume I was opaque watercolors on mica, and Volume II was watercolor on European and Indian papers. Mica is a material that is used in make-up and the mining industry. It is chemically inert, stable, and somewhat flammable. It is a cheap substitute for colored glass and lanterns.
They started the project in 2007 by removing the papers from the acidic album paper using traditional paper conservation techniques. This revealed ink inscriptions on the verso of the watercolors. Once digitized, these were encapsulated and housed in boxes and also on the NYPL online gallery. There were 29 pages total with 135 mica paintings. The full extent of the damage was now clear.
Reidell stated that since she is not a paintings conservator or an objects conservator, her aim was stabilization for future exhibition. The mica paintings were marketed for westerners, and the Victoria and Albert Museum and British Library have large holdings of mica paintings. The NYPL mica paintings had catastrophic media condition because the mica was damaged. None of the conventional paper techniques were suitable. Reidell used PLM and known McCrone samples to confirm that it was mica and not cellulose nitrate.
Relative humidity and temperature fluctuations were apparent in the albums and mica paintings. There was paint on the verso to create shadows and there was major media loss and damage to the lining and mica. Reidell tried cast fills using B-72, which didn’t work because it was not even and trapped dust. In-painting was also not an option because there was too much damage and loss. Consolidation with an ultrasonic mister did not work because everything was water-soluble. The damage was extensively documented and the works were put in temporary mats. Due to a previous mounting, the versos had even more damage. After testing JunFunori, Isinglass, methyl cellulose, Paraloid B-72, and Aquazol, Aquazol was chosen. Aquazol’s refractive index was the closest to the mica and various types of Aquazol were used for consolidation of large flakes, wetting out cupped or lifted flakes, and general consolidation and cohesion. B-72 was used for adhering large flakes of mica together.
The work flow consisted of using Excel for notes, copies of slides to color-map (using different colors for different adhesives, and silicon shapers to hold down flakes. After consolidation, the paper linings were removed and worked under the microscope on a Teflon-coated board. To repair the mica, BEVA 371 was used for fills and B-72 was used for complex tears.
After treatment, the paintings were digitized before mounting. Mounting was a challenge because Reidell needed to determine how to mount the paintings without messing up the micas but still enabling access. BEVA 371 film was attached Mylar-to-Mylar. BEVA 371 was used because it is pre-made, has a consistent thickness, and is fast. A silicone-coated Mylar barrier was used because it left no cloudy surface, unlike silicone-release paper barrier.
Finally, the project was publicized on social media and reached over 550,000 people through twitter, Instagram, Vine vidoes, and much more!

42nd Annual Meeting – Collections Care + HVAC Session, May 31, "The Road to Sustainable Environmental Management of Storage Conditions at the National Archives by Kostas Ntanos"

The National Archives is the official government archives of the UK and Wales. The Archives has two buildings: Q1, a building built in 1978 with three main repositories in three floors, and Q2, a newer building built in 1996 with twelve repositories over four floors.
Ntanos started by looking into records from 1973-75 to see the decision-making of how the Q1 building was designed. During this time from 1973-75, the staff discussed the requirements of environmental control and determined that temperature was more important than relative humidity and felt that if you kept temperature at mid-range, the RH would be controlled, too! Seven to eight years of mold growth prompted investigation into this building. Intensive climate-mapping was done using data loggers to determine the differences in the environment, and they saw a big difference between the center of the room (50-55%) and the ends of the room (70%).
Ntanos also used environmental assessment permanence maps to demonstrate how the environment changes through the year (he gave a poster at this AIC meeting on the mapping of material types). Once they had collected 1-2 years of information, they started making changes.
They used Energy Plus Software and put in as much information as possible about the environment and the building. They also used HAMT (Humidity and Moisture Transfer) and saw a difference with and without HAMT because of the large collection of hygroscopic material. The aim of the model was to examine options in maintaining a sustainable preservation environment for the collection. They were able to reduce energy consumption in line with sustainability targets, build resilience in light of climate change predictions, and inform ongoing capital investment. Powering down the HVAC over the weekend saved up 22% without affecting the preservation environment.

ECPN Webinar on April 23rd on Conservation Education, Outreach, and Advocacy

The Emerging Conservation Professionals Network (ECPN) is pleased to announce that our fourth webinar – “Get Involved! Conservation Education, Outreach, and Advocacy Webinar” – will take place on Wednesday, April 23rd from 12:00-1:00pm EST.
The program will feature three speakers with experience working in various aspects of conservation education, outreach, and advocacy: Teresa Myers, private practice conservator who participated in the American Alliance of Museum’s Museum Advocacy Day in 2011; Richard McCoy, an arts and cultural consultant with an established history of writing for digital and print publications, teaching in graduate programs, and creating innovative web projects; and Sarah Barack, private practice conservator and co-chair of AIC’s K-12 Educational Outreach subcommittee.
Participants will have the opportunity to ask questions before and after the webinar here on the AIC blog, as well as during the webinar in a Q&A session. Please submit your questions as comments to this post, or email them to Anisha Gupta at agupta[at]udel[dot]edu. Questions will be accepted until the morning of the webinar, during which  your questions will be posed anonymously. All unanswered questions at the end of the program will be addressed in an AIC blog post following the webinar.
Attendance is free and open to all AIC members. Registration is required and will be open until the webinar begins on April 23rd. To register, please visit https://www2.gotomeeting.com/register/898099178.
In addition to this webinar, ECPN has hosted three webinars in the past that address a diverse group of subjects. To view two of the programs, please see the links below. The recording of ECPN’s third webinar, “How to make the most of your pre-program internship,” which featured two speakers with experience supervising pre-program interns, Emily Williams and Thomas Edmondson; and two speakers with more recent experience as pre-program interns, LeeAnn Gordon and Ayesha Fuentes is forthcoming.
Self-advocacy and fundraising for independent research” with Debra Hess Norris, July 2012.
Follow-up Q&A to “Considering your future career path: working in private practice” with Rosa Lowinger, Julia Brennan, and Paul Messier, November 2012
For more information on ECPN’s webinar series, please visit www.conservation-us.org/ecpnforum.

How to Make the Most of Your Pre-Program Internship: About the Speakers

ECPN is getting excited for our upcoming webinar, “How to make the most of your pre-program internship,” featuring Emily Williams, Tom Edmondson, LeeAnn Barnes Gordon, and Ayesha Fuentes. The webinar will take place on Tuesday, September 24th from 12-1pm ET. To register for the program, please visit: https://www2.gotomeeting.com/register/766549178.
Get to know our speakers by reading their bios below and send in any questions about pre-program internships that you’d like them to discuss by commenting on this post or emailing Anisha Gupta at agupta[at]udel[dot]edu.
Emily Williams has an M.A. (1994) in the Conservation of Historic Objects (Archaeology) from the University of Durham in England.  During graduate school she did placements at the Museum of London, the British Museum and the Institute of Nautical Archaeology in Bodrum, Turkey. Since 1995, she has worked at the Colonial Williamsburg Foundation, where she is the current Conservator of Archaeological Materials. While at Colonial Williamsburg she spent five months working at the Western Australian Maritime Museum in Fremantle, Australia.  She has worked on excavations in Tunisia and Belgium; served as the site conservator at Tell Banat in Syria, Tell Umm el Marra in Syria, and Kurd Qaburstan in Iraqi Kurdistan; and taught courses on the conservation of waterlogged organics in Egypt.
Emily teaches HISP 208: Introduction to Conservation at the University of Mary Washington in Fredericksburg, Virginia. She has been a Professional Associate of AIC since 2000, and is presently serving as the chair of the Education and Training Committee (ETC).
Tom Edmondson was apprentice-trained in paper conservation theory and techniques at the New England Document Conservation Center (NEDCC), North Andover, MA (now the NEDCC, Andover, MA).  Following his training Tom operated a private practice paper conservation studio in Torrington, Connecticut, from April 1978 until August 1987.  In 1987 he closed his studio and took the position of Senior Paper Conservator at the Conservation Center, Panhandle-Plains Historical Museum in Canyon, Texas.  Shortly after his arrival he was assigned the position of Chief Conservator of the Conservation Center, from which he resigned in September 1988, when he and Nancy Heugh, relocated to Kansas City, Missouri, to establish their current private practice of Heugh-Edmondson Conservation Services, LLC.  Tom has been a member of AIC since 1977, and was elected a Fellow in 1998.  He served as Co-Chair of the PMG Commentaries Committee and served two 2-year terms as Chair of the AIC-Photographic Materials Group. Tom also served 7 years on the AIC Membership Committee, the last three of which he was Chair.  Always advocates of mentoring aspiring conservators, Tom and his partner Nancy Heugh are the 2011 recipients of AIC’s prestigious Sheldon and Caroline Keck Award in recognition of their sustained record of excellence in the education and training of conservation professionals.
LeeAnn Barnes Gordon earned her M.S. in Art Conservation from the Winterthur/University of Delaware Program in Art Conservation where she trained as an objects conservator. For the past two years she worked for the Museum of Fine Arts, Boston as the Sherman Fairchild Fellow in Objects Conservation and was the Conservator for the Athienou Archaeological Project in Cyprus. Prior to graduate school, LeeAnn completed internships in conservation at the Science Museum of Minnesota, the Midwest Art Conservation Center, with a conservator in private practice in Minneapolis, the Cincinnati Art Museum, and the Athienou Archaeological Project.
Ayesha Fuentes is a current 3rd year student at the UCLA/Getty MA Program in Conservation of Archaeological and Ethnographic Materials. She has worked pre-program internships with private practice paintings conservators in Seattle and Ipswich, MA as well as the Objects Conservation Lab at the MFA, Boston. She is currently completing part of her third-year internship at the Department of Culture, Thimphu, Bhutan. As a conservation graduate student, she also has worked at museum and governmental labs in Los Angeles, China, and Sri Lanka.

ECPN Webinar on September 24: “How to make the most of pre-program internships”

The Emerging Conservation Professionals Network (ECPN) is pleased to announce that our third webinar “How to make the most of your pre-program internship” will take place on Tuesday, September 24th from 12:00-1:00 EDT.
The program will feature two speakers with experience supervising pre-program interns, Emily Williams, Conservator of Archaeological Materials, The Colonial Williamsburg Foundation, and Thomas Edmondson, Paper & Photograph Conservator, Private Practice; and two speakers with more recent experience as pre-program interns, LeeAnn Gordon, Sherman Fairchild Fellow in Objects Conservation, and Ayesha Fuentes, Conservation Intern, Division for Cultural Properties, Department of Culture, Thimphu, Bhutan.
The webinar will include a moderated discussion and Q&A session, where we will learn about navigating pre-program internships and tips on how to maximize your experience.
Participants will have the opportunity to ask questions before and after the webinar here on the AIC blog. Please submit your questions as comments to this post, or email them to Anisha Gupta at agupta[at]udel[dot]edu. Questions will be accepted until the morning of the forum. During the webinar, your questions will be posed anonymously. All unanswered questions will be followed up on after the program in an AIC blog post.
Attendance is free and open to all AIC members. Registration is required and will be open until the forum starts. To register for the webinar, please visit https://www2.gotomeeting.com/register/766549178.
ECPN’s first webinar was held in July 2012 and featured Debra Hess Norris in a presentation and discussion on self-advocacy and fundraising for independent research. With over 90 registered participants from 6 different countries, the webinar was a great success. ECPN’s second webinar, in November 2012, featured three speakers in private practice: Rosa Lowinger, Julia Brennan, and Paul Messier. The webinar included a discussion of their experiences establishing their businesses and their evolution, how they have learned to balance various initiatives and projects, and their advice for those considering going into private practice.
“Self-advocacy and fundraising for independent research” with Debra Hess Norris, July 2012
http://www.youtube.com/watch?v=fDWgqY8umqQ
Follow-up Q&A to “Considering your future career path: working in private practice” with Rosa Lowinger, Julia Brennan, and Paul Messier, November 2012

For more information, please visit www.conservation-us.org/ecpnforum.

41st Annual Meeting – ECPN Happy Hour sponsored by Tru Vue, May 29

Photo courtesy of Molly Gleeson.
Photo courtesy of Molly Gleeson.

 
This year, the Emerging Conservation Professionals Network’s (ECPN) Happy Hour was sponsored by Tru Vue, who generously provided food and drink tickets. It was a great success, with at least 100 attendees. Since the Happy Hour was on Wednesday, it was a great opportunity to mingle and relax before launching into the busy conference. It also directly followed ECPN’s Portfolio Seminar, which provided a nice segue and allowed participants to continue their conversation over food and drinks. We hope you’ll join us at next year’s Happy Hour in San Francisco!
Photo courtesy of Molly Gleeson.
Photo courtesy of Molly Gleeson.

 

41st Annual Meeting – Architecture Session, May 30, "An Evaluation of the Conservation History of Chagall's Les Quatre Saisons," by Jamie Clapper Morris

Marc Chagall's Les Quatre Saisons
Marc Chagall’s Les Quatre Saisons (1974), Chase Tower Plaza, Chicago

Jamie Clapper Morris, an associate at Wiss, Janney, Elsther Associates, Inc. presented this paper on behalf of Deborah Slaton, principal at Wiss, Janney, Elsther Associates, Inc. and herself.
Les Quatre Saisons is a mosaic by artist Marc Chagall, which is exhibited in a public plaza in the Loop district in downtown Chicago. It was a gift from Chagall to the people of Chicago in 1974, and it is located at the Chase Tower Plaza (formerly First National Bank of Chicago Plaza). The mosaic has tesserae placed on precast concrete panels with more than 250 colors. It was constructed in the Byzantine Style and assembled in southern France.
The original maintenance on this piece included biannual cleaning and annual sealing with silicon sealant. In 1988, the roof of the mosaic had completely deteriorated with 25% loss on the west side. In order to repair it, granite panels were put on the roof. In places where tesserae had fallen off, they were reinstalled in slightly different way in order to distinguish it from the original. In 1993, a bird deterrent gel was added but then removed because of staining. Visual assessment and lab studies were performed, including chemical analysis and scanning  electron microscopy studies. The majority  of the distress was on the west side. From 1995 to 1996, repairs were being performed on the adjacent plaza, and the mosaic was protected with an enclosure. A protective canopy was built for the mosaic, and wind tunnel studies were performed to ensure maximum protection. When repairing the mosaic, a lot of tesserae from the roof were used. The canopy was finished in 1996.
From 2009 to 2010, facade cleaning and limited condition assessments were performed, including some sounding and field microscopy. Expected distress was found. In 2011, a more detailed assessment was performed and it was sounded at 100% with xylophone mallets. Some  expected distress included efflorescence and mortar loss. Limited maintenance was performed, including removing general atmospheric soiling, graffiti, and bird deterrent (which didn’t work). It was surface cleaned, and the graffiti was removed with acetone and water. Areas of loss were repaired and tesserae were re-installed. Ongoing maintenance is recommended.

The Art Conserver: How conservation professionals make use of online resources

This blog post accompanies the Emerging Conservation Professionals Network (ECPN)’s poster at AIC’s 41st Annual Meeting: The Art_Con<server>: How conservation professionals make use of online resources, which captured and analyzed preferences in our field regarding the creation and use of conservation information online. The content for the poster was generated based on a survey distributed to AIC members. In this survey, respondents were asked to rate their usage and preferences about various online resources. These resources are summarized in this post.

  • AATA: This Getty-run site is “a comprehensive database of over 120,000 abstracts of literature related to the preservation and conservation of material cultural heritage”.
  • AIC website: The American Institute for Conservation (AIC) website has resources for conservators and the public. These include academic journals, the member newsletter, and helpful guides.
  • AIC Wiki: The AIC Wiki has sections for each of the specialty groups, drawing information from different resources, including the print conservation catalogs. This “platform allows for easy and timely collaborative editing and also provides much broader access to these resources, ensuring that innovative methods and materials are documented and widely disseminated to practicing conservators and conservation scientists.”
  • American Alliance of Museums (AAM) Resource Center: Resources for museums include collections stewardship, financial stability, and marketing and public relations.
  • Bibliographic Database of the Conservation Information Network (BCIN): One of the “most complete bibliographic resources for the conservation, preservation and restoration of cultural property”.
  • Canadian Conservation Institute (CCI) website: The CCI website includes many documents and links, including resources from other Canadian heritage organizations.
  • CoOL: A centralized repository covering over twenty-five preservation and conservation topics.
  • CoOL DistList archives: The Conservation DistList is an email distribution list and an interdisciplinary forum open to conservators, conservation scientists, curators, librarians, archivist, administrators, and others involved in the preservation of cultural property. The archives include posts dating back to 1987.
  • Getty Conservation Institute (GCI) website: The GCI site includes an e-bulletin, digital collections, a large library of free PDF versions of GCI publications, and article and research databases.
  • Google Scholar: Search for scholarly work in all disciplines.
  • JSTOR: A digital library of academic journals.
  • National Park Service (NPS) website: The NPS has handy Conserve-O-Grams, “short, focused leaflets about caring for museum objects, published in loose-leaf format”. They cover all of the various specialty groups, as well as disaster response and collection care.
  • Wikipedia: A free encyclopedia that can be edited by the public.
  • WorldCat: The largest network of library content and services, WorldCat allows the user to search for libraries all over the world.

Of course there are a large number of other very useful resources for our field. What resources do you find yourself referencing most often? Do you have an interesting resource to share? Please leave comments so that others can know about them.