Nagel, T. S., & Richman, P. T. (1972). Competency-based instruction: A strategy to eliminate failure; a branching programmed text. C.E. Merrill Pub.
Čikaški stil citiranja (17. izdanje)Nagel, Thomas S., i Paul T. Richman. Competency-based Instruction: A Strategy to Eliminate Failure; a Branching Programmed Text. Columbus, Ohio: C.E. Merrill Pub, 1972.
MLA način citiranja (9. izdanje)Nagel, Thomas S., i Paul T. Richman. Competency-based Instruction: A Strategy to Eliminate Failure; a Branching Programmed Text. C.E. Merrill Pub, 1972.
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