APA (7th ed.) Citation

United States. Library of Congress. (1990). Library of Congress classification schedules combined with additions and changes through 1989: Class C Auxiliary sciences of history. Gale Research.

Chicago Style (17th ed.) Citation

United States. Library of Congress. Library of Congress Classification Schedules Combined with Additions and Changes Through 1989: Class C Auxiliary Sciences of History. Detroit: Gale Research, 1990.

MLA (9th ed.) Citation

United States. Library of Congress. Library of Congress Classification Schedules Combined with Additions and Changes Through 1989: Class C Auxiliary Sciences of History. Gale Research, 1990.