Não informado. (1989). Adults Learning. National Institute of Adult Continuing Education.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Adults Learning. Leicester, Inglaterra: National Institute of Adult Continuing Education, 1989.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Adults Learning. National Institute of Adult Continuing Education, 1989.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.