@book{2076,
	author = {Gabbe, Steven G. and Niebyl, Jennifer R.},
	title = {Obstetrics :},
	publisher = {Elsevier/Saunders,},
	year = {2012.},
	address = {Philadelphia :},
	edition = {6th ed.},
	url = {https://books.google.com.pk/books?id=x3mJpT2PkEUC&pg=PA1293&dq=Obstetrics+:+normal+and+problem+pregnancies+6th+ed.&hl=en&sa=X&ved=2ahUKEwiD-tvnkLv1AhVQ_aQKHVIIBx4Q6AF6BAgLEAI#v=onepage&q=Obstetrics%20%3A%20normal%20and%20problem%20pregnancies%206th%20ed.&f=false}
}