Burger, W. V. (1935). Teacher's manual for Ditto directed study lessons in American history. Ditto, Inc..
Chicago-referens (17:e uppl.)Burger, William V. Teacher's Manual for Ditto Directed Study Lessons in American History. Chicago: Ditto, Inc., 1935.
MLA-referens (8:e uppl.)Burger, William V. Teacher's Manual for Ditto Directed Study Lessons in American History. Ditto, Inc., 1935.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.