@article{Hu2016,
author = {Hu, A. and Mustillo, S.},
title= {Recent development of propensity score methods in observational studies: Multi-categorical treatment, causal mediation, and heterogeneity},
year = {2016},
doi = {10.1177/0011392115589599},
volume = {64},
number = {1},
pages = {60--82},
}