@inbook{Uhlenberg1998,
author = {Uhlenberg, P. and Kirby, J.B.},
title= {Grandparenthood over time: Historical and demographic trends},
year = {1998},
editor = {Szinovacz, M.E.},
booktitle = {Handbook on Grandparenthood},
address = {Westport},
publisher = {Greenwood Press},
pages = {23--39},
}