@article{Frejka2006,
author = {Frejka, T. and Sardon, J. P.},
title= {First birth trends in developed countries: Persisting parenthood postponement},
year = {2006},
doi = {10.4054/DemRes.2006.15.6 },
journal = {Demographic Research},
volume = {15},
number = {6},
pages = {147--180},
}