@inbook{Beard1959,
author = {Beard, R.},
title= {Notes on some mathematical mortality models},
year = {1959},
editor = {Wolstenholme, G.},
editor = {O’Connor, M. },
booktitle = {The lifespan of animals},
address = {Boston},
publisher = {Little, Brown},
pages = {802--811},
}