@article{Caliendo2008,
author = {Caliendo, M. and Kopeinig, S.},
title= {Some practical guidance for the implementation of propensity score matching},
year = {2008},
doi = {10.1111/j.1467-6419.2007.00527.x},
volume = {22},
number = {1},
pages = {31--72},
}