Rubin, Donald2015-07-072010Rubin, Donald B. 2010. “Propensity Score Methods.” American Journal of Ophthalmology 149 (1) (January): 7–9. doi:10.1016/j.ajo.2009.08.024.0002-9394http://nrs.harvard.edu/urn-3:HUL.InstRepos:17115450en-USPropensity Score MethodsJournal Article10.1016/j.ajo.2009.08.024