Version history for Duncan L. Copp and John E. Guest, 2007, Geologic map of the Sif Mons quadrangle (V-31), Venus: U.S. Geological Survey Scientific Investigations Map 2989. [http://pubs.usgs.gov/sim/2007/2989/]. Version 1.0, July 30, 2007 Initial release online at http://pubs.usgs.gov/sim/2007/2989/