Não informado. (1971). NLL Announcement Bulletin. National Lending Library for Science and Technology.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. NLL Announcement Bulletin. Boston, Inglaterra: National Lending Library for Science and Technology, 1971.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. NLL Announcement Bulletin. National Lending Library for Science and Technology, 1971.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.