@book{34210,
	author = {Williams, J. Whitridge and Cunningham, F. Gary,},
	title = {Williams obstetrics /},
	publisher = {McGraw-Hill Education,},
	year = {[2018]},
	address = {New York :},
	edition = {25th edition.},
	url = {https://obgyn.mhmedical.com/book.aspx?bookID=1918}
}