Efficacy and safety of sodium phosphate tablets compared with PEG solution in colon cleansing: two identically designed, randomized, controlled, parallel group, multicenter phase III trials. - Kastenberg,D.; Chasen,R.; Choudhary,C.; Riff,D.; Steinberg,S.; Weiss,E.; Wruble,L. (Gastrointest Endosc, 2001)