@article{Kohler2002,
author = {Kohler, H.-P. and Billari, F. and Ortega, J.A.},
title= {Towards a theory of lowest-low fertility},
year = {2002},
doi = {10.1111/j.1728-4457.2002.00641.x},
journal = {Population and Development Review },
volume = {28},
number = {4},
pages = {641--680},
}