Burger, W. V. (1935). Teacher's manual for Ditto directed study lessons in American history. Ditto, Inc..
Chicago-viite (17. p.)Burger, William V. Teacher's Manual for Ditto Directed Study Lessons in American History. Chicago: Ditto, Inc., 1935.
MLA-viite (8. p.)Burger, William V. Teacher's Manual for Ditto Directed Study Lessons in American History. Ditto, Inc., 1935.
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