@phdthesis{Sobotka2004,
author = {Sobotka, T.},
title= {Postponement of childbearing and low fertility in Europe},
year = {2004},
doi = {10.1111/j.1728-4457.2004.010_1.x},
type = {PhD Thesis},
address = {Amsterdam},
institution = {Dutch University Press},
publisher = {University of Groningen},
}