@article{Sullivan2005,
author = {Sullivan, R.},
title= {The Age Pattern of First-Birth Rates Among U.S. Women: The Bimodal 1990s},
year = {2005},
doi = {10.1353/dem.2005.0018},
journal = {Demography},
volume = {42},
number = {2},
pages = {259--273},
}