Rosen AK, Loveland SA, Romano PS, Itani KM, Silber JH, Even-Shoshan OO, Halenar MJ, Teng Y, Zhu J, Volpp KG. Effects of resident duty hour reform on surgical and procedural patient safety indicators among hospitalized Veterans Health Administration and Medicare patients. Med Care. 2009 Jul; 47(7):723-31.