@techreport{Brass1981,
author = {Brass, W. and Bamgboye, E.},
title= {The time location of reports of survivorship: Estimates for maternal and paternal orphanhood and the ever-widowed},
year = {1981},
publisher = {London School of Hygiene and Tropical Medicine: Centre for Population Studies},
number = {research paper 81-1},
}