Ice in the Polar Regions of Mars: Evidence for Wet Periods in the Recent Past Boynton, W. V. ; Chamberlain, M. ; Feldman, W. C. ; Prettyman, T. ; Hamara, D. ; Janes, D. ; Kerry, K. ; GRS Team Abstract Publication: Third International Conference on Mars Polar Science and Exploration Pub Date: October 2003 Bibcode: 2003mpse.conf.8133B