@book{Gwatkin2007,
author = {Gwatkin, D.R. and Rutstein, S. and Johnson, K. and Suliman, E. and Wagstaff, A. and Amouzou, A.},
title= {Socio-economic differences in health, nutrition, and population within developing countries: An overview},
year = {2007},
address = {Washington, D.C.},
publisher = {The World Bank},
}