@article{Coale1991,
author = {Coale, A. and Wang, F. and Riley, N. E. and De, L.F.},
title= {Recent trends in fertility and nuptiality in China},
year = {1991},
doi = {10.1126/science.251.4992.389},
journal = {Science},
volume = {251},
number = {4992},
pages = {389−393},
}