Shenton, J. P., & Meckler, A. M. (1973). Programmed learning aid for United States history. Learning Systems.
Citazione stile Chigago Style (17a edizione)Shenton, James Patrick, e Alan M. Meckler. Programmed Learning Aid for United States History. Homewood, Ill: Learning Systems, 1973.
Citatione MLA (9a ed.)Shenton, James Patrick, e Alan M. Meckler. Programmed Learning Aid for United States History. Learning Systems, 1973.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.