Chatzi L, Plana E, Pappas A, Alegkakis D, Karakosta P, Daraki V. The metabolic syndrome in early pregnancy and risk of gestational diabetes mellitus. Diabetes Metab. 2009 Dec;35(6):490-4.
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