APA (7 वां संस्करण) प्रशस्ति पत्र
Egan, G., & Cowan, M. (1979). People in systems: A model for development in the human-service professions and education. Brooks/Cole.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्र
Egan, Gerald, और Michael Cowan. People in Systems: A Model for Development in the Human-service Professions and Education. Monterey, Calif: Brooks/Cole, 1979.
एमएलए (9वां संस्करण) प्रशस्ति पत्र
Egan, Gerald, और Michael Cowan. People in Systems: A Model for Development in the Human-service Professions and Education. Brooks/Cole, 1979.
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