U.S. Geological Survey Karst Interest Group
U.S. Geological Survey Karst Interest Group proceedings- U.S. Geological Survey Karst Interest Group proceedings, Rapid City, South Dakota, September 12-15, 2005
- U.S. Geological Survey Karst Interest Group proceedings, Shepherdstown, West Virginia, August 20-22, 2002
- U.S. Geological Survey Karst Interest Group proceedings, St. Petersburg, Florida, February 13-16, 2001