Nagel, T. S., & Richman, P. T. (1972). Competency-based instruction: A strategy to eliminate failure; a branching programmed text. C.E. Merrill Pub.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNagel, Thomas S., और Paul T. Richman. Competency-based Instruction: A Strategy to Eliminate Failure; a Branching Programmed Text. Columbus, Ohio: C.E. Merrill Pub, 1972.
एमएलए (9वां संस्करण) प्रशस्ति पत्रNagel, Thomas S., और Paul T. Richman. Competency-based Instruction: A Strategy to Eliminate Failure; a Branching Programmed Text. C.E. Merrill Pub, 1972.
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