Ziegler, Andrew C.
Lawrence, Kan. : U.S. Dept. of the Interior, U.S. Geological Survey ; Denver, Colo. : Information Services [distributor], 1999.
1999
Christensen, Victoria G.
Lawrence, Kan. : U.S. Department of the Interior, U.S. Geological Survey ; Denver, Colo. : Information Services [distributor], 2000.
2000