@article{Morgan2006,
author = {Morgan, S.L. and Harding, D.J.},
title= {Matching estimators of causal effects: Prospects and pitfalls in theory and practice},
year = {2006},
doi = {10.1177/0049124106289164},
journal = {Sociological Methods and Research},
volume = {35},
number = {1},
pages = {3--60},
}