Ruskin, R. S. (1974). The personalized system of instruction: An educational alternative. Americam Association for Higher Education.
Chicago-viite (17. p.)Ruskin, Robert S. The Personalized System of Instruction: An Educational Alternative. Washington, D.C.: Americam Association for Higher Education, 1974.
MLA-viite (9. p.)Ruskin, Robert S. The Personalized System of Instruction: An Educational Alternative. Americam Association for Higher Education, 1974.
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