@article{Altonji2005,
author = {Altonji, J.G. and Elder, T.E. and Taber, C.R.},
title= {Selection on observed and unobserved variables: Assessing the effectiveness of Catholic schools},
year = {2005},
doi = {10.1086/426036},
volume = {113},
number = {1},
pages = {151--184},
}