Langley, B. C. (1990). Heating, ventilating, air conditioning, and refrigeration (4th ed.). Prentice-Hall.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रLangley, Billy C. Heating, Ventilating, Air Conditioning, and Refrigeration. 4th ed. Englewood Cliffs, N.J: Prentice-Hall, 1990.
एमएलए (9वां संस्करण) प्रशस्ति पत्रLangley, Billy C. Heating, Ventilating, Air Conditioning, and Refrigeration. 4th ed. Prentice-Hall, 1990.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.