Britt (DiBenedetti) DM, Collins FL, Cohen LM. Cigarette smoking and chewing gum use among college students. J Appl Biobehav Res. 2007 Jun 4;4(2):85-90. doi: 10.1111/j.1751-9861.1999.tb00057.x
Wenham RM, Calingaert B, Ali S, McClean K, Whitaker R, Bentley R, Lancaster JM, Schildkraut J, Marks J, Berchuck A. Matrix metalloproteinase-1 gene promoter polymorphism and risk of ovarian cancer. J Soc Gynecol Investig. 2003 Sep 1;10(6):381-7.