Authors: Stuart J Pocock; Timothy J Collier; Kimberley J Dandreo; Bianca L de Stavola; Marlene B Goldman; Leslie A Kalish; Linda E Kasten; Valerie A McCormack Journal: BMJ Date: 2004-10-06
Authors: Krista F Huybrechts; Kenneth J Rothman; Rebecca A Silliman; M Alan Brookhart; Sebastian Schneeweiss Journal: CMAJ Date: 2011-03-28 Impact factor: 8.262