@article{Li2018,
author = {Li, F. and Morgan, K.L. and Zaslavsky, A.M.},
title= {Balancing covariates via propensity score weighting},
year = {2018},
doi = {10.1080/01621459.2016.1260466},
volume = {113},
number = {521},
pages = {390--400},
}