@book{3633,
	author = {Barnett, Raymond A. and Ziegler, Michael R.},
	title = {Precalculus :},
	publisher = {McGraw-Hill,},
	year = {c1989.},
	address = {New York :},
	edition = {2nd ed.},
	url = {https://books.google.com.pk/books?id=6U0KzgEACAAJ&dq=Precalculus+:&hl=en&sa=X&redir_esc=y}
}