Classification.
Class Q: Science.

APA Citation

Library of Congress. Subject Cataloging Division., Gale Research Company., Library of Congress. Classification Division. Classification. (1950). Classification: Class Q: Science. 5th ed., with supplementary pages. Washington: U. S. Govt. Print. Off..

MLA Citation

Library of Congress. Subject Cataloging Division, Gale Research Company, and Library of Congress. Classification Division. Classification. Classification: Class Q: Science. 5th ed., with supplementary pages. Washington: U. S. Govt. Print. Off., 1950.