Ralph, Philip Lee World civilizations : their history and their culture / Philip Lee Ralph ... [et al.]. - 8th ed. - New York : W.W. Norton & Co., c1991. - xxiv, 800 p. ; ill. ; 23 cm. ISBN: 0393959155 LCCN: Subjects--Topical Terms: CivilizationHistory LC Class. No.: CB69 / .W67 1991