Cueto HT, Riis AH, Hatch EE, Wise LA, Rothman KJ, Sørensen HT, Mikkelsen EM. Folic acid supplementation and fecundability: a Danish prospective cohort study. Eur J Clin Nutr. 2016 Jan;70(1):66-71. doi: 10.1038/ejcn.2015.94
Cole JA, Rothman KJ, Cabral HJ, Zhang Y, Farraye FA. Incidence of IBS in a cohort of people with asthma. Dig Dis Sci. 2007 Feb 28;52(2):329-35.