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
Knoll S, Jochum D, Talbird S. Comparative cost benefit analysis of two new Pneumococcal Conjugate Vaccines (PHiD-CV and PCV-13). Klin Padiatr. 2010 Jun 1;222(Suppl 1):S51-2.