Sheldon, E. A. (1883). Lessons on objects, graduated series: Designed for children between the ages of six and fourteen years.
Citazione stile Chigago Style (17a edizione)Sheldon, Edward Austin. Lessons on Objects, Graduated Series: Designed for Children Between the Ages of Six and Fourteen Years. New York, 1883.
Citatione MLA (9a ed.)Sheldon, Edward Austin. Lessons on Objects, Graduated Series: Designed for Children Between the Ages of Six and Fourteen Years. 1883.
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