Version history for Gregg, Tracy K.P., Tanaka, Kenneth L., and Saunders, R. Stephen, eds., 2004, Abstracts of the Annual Meeting of Planetary Geologic Mappers: U.S. Geological Survey Open-File Report 2004-1100. Version 1.0, April 23, 2004 Intital release online at http://pubs.usgs.gov/of/2004/1100/