Sharp L, Donnelly D, Hegarty A, Carsin AE, Deady S, McCluskey N, Gavin A, Comber H. Risk of several cancers is higher in urban areas after adjusting for socioeconomic status. Results from a two-country population-based study of 18 common cancers. J Urban Health. 2014 Jun;91(3):510-25. doi: 10.1007/s11524-013-9846-3
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