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
Mordin M, Anastassopoulos K, van Breda A, Vallow S, Zhang M, Gargiulo K, Hewitt D, Olson W, Sikirica V. Clinical staff resource use with intravenous patient-controlled analgesia in acute postoperative pain management: results from a multicenter, prospective, observational study. J Perianesth Nurs. 2007 Aug 1;22(4):243-55.