Recommendations for the use of operational electronic health record data in comparative effectiveness research - Hersh, WR; Cimino, J; Payne, PR; Embi, P; Logan, J; Weiner, M; Bernstam, EV; Lehmann, H; Hripcsak, G; Hartzog, T; Saltz, J (EGEMS (Wash DC), 2013)