Library of Congress & Subjet Cataloging Division. (1998). Subject Headings (21th. ed.). The National Bibliographic Service.
芝加哥风格引文Library of Congress 与 Subjet Cataloging Division. Subject Headings. 21th. ed. Washington: The National Bibliographic Service, 1998.
MLA引文Library of Congress 与 Subjet Cataloging Division. Subject Headings. 21th. ed. The National Bibliographic Service, 1998.
警告：这些引文格式不一定是100％准确.