@inbook{Billari2006,
author = {Billari, F.C. and Philipov, D. and Liefbroer, A.C.},
title= {The postponement of childbearing in Europe: driving forces and implications},
year = {2006},
doi = {10.1553/populationyearbook2006s1},
booktitle = {Vienna Yearbook of Population Research},
pages = {1--17},
}