@article {4947,
	title = {The Emergence of Countercyclical US Fertility},
	journal = {The American economic review},
	volume = {69},
	year = {1979},
	pages = {318{\textendash}328},
	url = {https://www.jstor.org/stable/1807367},
	author = {Butz, William P. and Ward, Michael P.}
}
