Nutrition intervention trials in Linxian, China: Multiple vitamin/mineral supplementation, cancer incidence, and disease-specific mortality among adults with esophageal dysplasia. - Li,J.Y.; Taylor,P.R.; Li,B.; Dawsey,S.; Wang,G.Q.; Ershow,A.G.; Guo,W.; Liu,S.F.; Yang,C.S.; Shen,Q. (J Natl Cancer I, 1993)