Environmental Education Project (Portland, Or.). (1978). Clearing. Environmental Education Project.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रEnvironmental Education Project (Portland, Or.). Clearing. Portland, Or.: Environmental Education Project, 1978.
एमएलए (9वां संस्करण) प्रशस्ति पत्रEnvironmental Education Project (Portland, Or.). Clearing. Environmental Education Project, 1978.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.