@article{Espenshade2011,
author = {Espenshade, T.J. and Olgiati, A.S. and Levin, S.A.},
title= {On nonstable and stable population momentum},
year = {2011},
doi = {10.1007/s13524-011-0063-y},
volume = {48},
number = {4},
pages = {1581--1599},
}