@book{6861,
	author = {Lang, Serge,},
	title = {Calculus of several variables /},
	publisher = {Springer-Verlag,},
	year = {c1987.},
	address = {New York :},
	edition = {2nd ed.},
	note = {Includes index.},
	url = {http://www.loc.gov/catdir/enhancements/fy0814/86017724-d.html}
}