@inbook{Heckman1985,
author = {Heckman, J. and Singer, B.},
title= {Social science duration analysis},
year = {1985},
doi = {10.1017/CCOL0521304539},
editor = {Heckman, J.},
editor = {Singer, B.},
booktitle = {Longitudinal analysis of labor market data},
address = {Cambridge},
publisher = {Cambridge University Press},
pages = {39--110},
}