@inbook{Thatcher1998,
author = {Thatcher, A.R. and Kannisto, V. and Vaupel, J.W.},
title= {The force of mortality at ages 80 to 120},
year = {1998},
booktitle = {Monographs on Population Aging 5},
address = {Odense, Denmark},
publisher = {Odense University Press},
}