Cohen LM, Britt DM, Collins FL, Stott HD, Carter LC. Chewing gum affects smoking topography. Exp Clin Psychopharmacol. 1999 Nov 1;7(4):444-7.
Anderson JJB, Anthony M, Messina M, Garner SC. Effects of phyto-oestrogens on tissues. Nutr Res Rev. 1999 Jun;12(01):75-116.