@article{Harder2010,
author = {Harder, V.S. and Stuart, E.A. and Anthony, J.C.},
title= {Propensity score techniques and the assessment of measured covariate balance to test causal associations in psychological research},
year = {2010},
doi = {10.1037/a0019623},
volume = {15},
number = {3},
pages = {234},
}