Kramer, S. N. (1981). History begins at Sumer: Thirty-nine firsts in man's recorded history (3rd rev. ed.). Philadelphia: University of Pennsylvania Press.
استشهاد بنمط شيكاغوKramer, Samuel Noah. History Begins At Sumer: Thirty-nine Firsts in Man's Recorded History. 3rd rev. ed. Philadelphia: University of Pennsylvania Press, 1981.
MLA استشهادKramer, Samuel Noah. History Begins At Sumer: Thirty-nine Firsts in Man's Recorded History. 3rd rev. ed. Philadelphia: University of Pennsylvania Press, 1981.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.