@inbook{Cassel2002,
author = {Cassel, P.-G.},
title= {Changing seasonality of births in Sweden 1900–1999},
year = {2002},
editor = {Carling, J.},
booktitle = {Nordic demography: Trends and differentials},
address = {Oslo},
publisher = {Nordic Demographic Society},
pages = {97--110},
}