+ of +Gilgamesh%22&num=100& client = opera & sig =ACfU3U19bQtV0FbzQHz00tu38-cpnaTj3g .   Jacobsen, Thorkild (1976). The Treasures of Darkness , A History of Mesopotamian Religion . Yale University Press . ISBN   0-300-01844-4 . http://books.google. com /books? id =pD17nsgWQBoC&dq=%22The+Treasures+ of + Darkness ,+ A + History + of +Mesopotamian+ Religion %22&pg=PP1&ots=xIB1vOkUgr& sig