@book{242,
	author = {Gustafson, R. David},
	title = {Plane trigonometry / David Gustafson R.},
	publisher = {Pacific Grove, Calif. : Brooks/Cole Pub. Co.,  c1994.},
	address = {Pacific Grove, Calif. : Brooks/Cole Pub. Co.,  c1994.},
	edition = {4th ed.}
}