@article{Li2013,
author = {Li, N. and Lee, R. and Gerland, P.},
title= {Extending the Lee–Carter Method to Model the Rotation of Age Patterns of Mortality Decline for Long-Term Projections},
year = {2013},
doi = {10.1007/s13524-013-0232-2},
volume = {50},
number = {6},
pages = {2037--2051},
}