Bossing, N. L. (1944). Progressive methods of teaching in secondary school. Houghton Mifflin.
Chicago-čujuhus (17. p.)Bossing, Nelson L. Progressive Methods of Teaching in Secondary School. Houghton Mifflin, 1944.
MLA-čujuhus (9. p.)Bossing, Nelson L. Progressive Methods of Teaching in Secondary School. Houghton Mifflin, 1944.
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