Cainzos-Achirica M, Bilal U, Kapoor K, Quispe Ayala R, McEvoy JW, Pladevall-Vila M, Blumenthal RS, Blaha MJ. Methodological issues in nutritional epidemiology research–sorting through the confusion. Current Cardiovascular Risk Reports. 2018 Feb;12:4. doi: 10.1007/s12170-018-0567-8
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.