@article{Heligman1980,
author = {Heligman, L. and Pollard, J.H.},
title= {The age pattern of mortality},
year = {1980},
doi = {10.1017/S0020268100040257},
journal = {Journal of the Institute of Actuaries},
volume = {107},
number = {1},
pages = {49--80},
}