Library of Congress & Subjet Cataloging Division. (1998). Subject Headings (21th. ed.). The National Bibliographic Service.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रLibrary of Congress और Subjet Cataloging Division. Subject Headings. 21th. ed. Washington: The National Bibliographic Service, 1998.
एमएलए (9वां संस्करण) प्रशस्ति पत्रLibrary of Congress और Subjet Cataloging Division. Subject Headings. 21th. ed. The National Bibliographic Service, 1998.