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
Strickland A, Brogan AJ, Krauss J, Martindale R, Cresci G. Is the use of specialized nutritional formulations a cost-effective strategy? A national database evaluation. J Parenter Enter Nutr. 2005 Jan 1;29(1 Suppl):S81-91.