Kramer, S. N. 1. (1981). History begins at Sumer: Thirty-nine firsts in recorded history (Third revised edición.). Philadelphia: University of Pennsylvania Press.
Chicago Style CitationKramer, Samuel Noah 1897-1990. History Begins At Sumer: Thirty-nine Firsts in Recorded History. Third revised edición. Philadelphia: University of Pennsylvania Press, 1981.
MLA CitationKramer, Samuel Noah 1897-1990. History Begins At Sumer: Thirty-nine Firsts in Recorded History. Third revised edición. Philadelphia: University of Pennsylvania Press, 1981.
Warning: These citations may not always be 100% accurate.