Hartley, W. H. (1950). A guide to audio-visual materials for elementary school social studies. Rambler Press.
Chicago-viite (17. p.)Hartley, William H. A Guide to Audio-visual Materials for Elementary School Social Studies. [Brooklyn, New York]: Rambler Press, 1950.
MLA-viite (9. p.)Hartley, William H. A Guide to Audio-visual Materials for Elementary School Social Studies. Rambler Press, 1950.
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