@article{Happel1984,
author = {Happel, S. and Hill, J.K. and Low, S.},
title= {An economic analysis of the timing of child-birth},
year = {1984},
doi = {10.1080/00324728.1984.10410291},
journal = {Population Studies},
volume = {38},
number = {2},
pages = {299--311},
}