@inbook{van de Walle1993,
author = {van de Walle, E.},
title= {Recent trends in marriage ages},
year = {1993},
editor = {Foote, K. A.},
editor = {Hill, K. H.},
editor = {Martine, L. G.},
booktitle = {Demographic Change in sub-Saharan Africa},
address = {Washington, D.C.},
publisher = {National Research Council, National Academy Press},
}