Fondell E, Lagerros YT, Sundberg CJ, Lekander M, Balter O, Rothman KJ, Balter K. Physical activity, stress, and self-reported upper respiratory tract infection. Med Sci Sports Exerc. 2011 Feb 1;43(2):272-9.
Strickland A, Brogan AJ, Krauss J, Martindale R, Cresci G. Is the use of specialized nutritional formulations a cost-effective strategy? A national database evaluation. J Parenter Enter Nutr. 2005 Jan 1;29(1 Suppl):S81-91.
Zarkin GA, Bray JW, Davis KL, Babor TF, Higgins-Biddle JC. The costs of screening and brief intervention for risky alcohol use. J Stud Alcohol. 2003 Jan 1;64(6):849-57.