@article{Rees2012,
author = {Rees, P. and Gaag, N. and Beer, J. and Heins, F.},
title= {European regional populations: Current trends, future pathways, and policy options},
year = {2012},
doi = {10.1007/s10680-012-9268-z},
volume = {28},
number = {4},
pages = {385--416},
}