@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},
URL = {http://www.demogr.mpg.de},
booktitle = {Monographs on Population Aging 5},
address = {Odense, Denmark},
publisher = {Odense University Press},
}