Raghunathan K, Layton JB, Ohnuma T, Shaw AD. Observational research using propensity scores. Adv Chronic Kidney Dis. 2016 Nov;23(6):367-72. doi: 10.1053/j.ackd.2016.11.010
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.
DePyssler B, Williams VSL, Windle M. Alcohol consumption and positive study practices among African American college students. J Alcohol Drug Educ. 2005 Dec 1;49(4):26-44.