@article{Li2013,
author = {Li, Nan and Lee, Ronald and Gerland, Patrick},
title= {Extending the Lee-Carter method to model the rotation of age patterns of mortality decline for long-term projections.},
year = {2013},
URL = {10.1007/s13524-013-0232-2},
journal = {Demography},
volume = {50},
number = {6},
pages = {2037--2051},
}