Gaya APA

Beal, S, J., Kupzyk, K, A. (2013). An Introduction to Propensity Scores: What, When, and How (Vol 34(1) 66– 92). U.S.A: SAGE.

Gaya MLA

Beal, Sarah, J.., Kupzyk, Kevin, A.. "An Introduction to Propensity Scores: What, When, and How". Vol 34(1) 66– 92 U.S.A: SAGE, 2013. e-journal.