@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 = {Doctoral thesis},
address = {Amsterdam},
publisher = {University of Groningen, Dutch University Press},
}