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
French M, Neighbors D, Carswell L, Williams R, Bush L. A model for estimating industry compliance costs of food labeling regulations. Agribusiness: An International Journal. 1993;8(2):165-86.
Lawson DH, Jick H, Rothman KJ. Coffee and tea consumption and breast disease. Surgery. 1981 Jan 1;90(5):801-3.