Osborne, Tom. The economics machine : a study guide / Tom Osborne & John Foreman. - 16th ed. 2006 edition - Happy Valley, S. Aust. : Fossick Publishers, 2006. - 173 p. ; 30 cm. ISBN: 0949606332 (pbk.) Subjects--Topical Terms: Economics Dewey Class. No.: 330 / OSB