Steensberg, A. (1989). Hard grains, irrigation, numerals and script in the rise of civilizations. Copenhagen: Royal Danish Academy of Sciences and Letters' Commission for Research on the History of Agricultural Implements and Field Structures.
استشهاد بنمط شيكاغوSteensberg, Axel. Hard Grains, Irrigation, Numerals and Script in the Rise of Civilizations. Copenhagen: Royal Danish Academy of Sciences and Letters' Commission for Research on the History of Agricultural Implements and Field Structures, 1989.
MLA استشهادSteensberg, Axel. Hard Grains, Irrigation, Numerals and Script in the Rise of Civilizations. Copenhagen: Royal Danish Academy of Sciences and Letters' Commission for Research on the History of Agricultural Implements and Field Structures, 1989.