Reproductive factors and risks of biliary tract cancers and stones: a population-based study in Shanghai, China.
Andreotti G, Hou L, Gao YT, Brinton LA, Rashid A, Chen J, Shen MC, Wang BS, Han TQ, Zhang BH, et al. Br J Cancer. 2010 Mar 30; 102(7):1185-9. Epub 2010 Mar 9.