Classification :
Library of Congress Subject Cataloging Division
Classification : Class Q : Science. - 5th ed. (with supplementary pages) - Washington : Govt. print. off, 1950 (reprinted 1954). - 216, 15 p.
Classification--Books--Science
Classification, Library of Congress
Classification--Books--General works
Classification : Class Q : Science. - 5th ed. (with supplementary pages) - Washington : Govt. print. off, 1950 (reprinted 1954). - 216, 15 p.
Classification--Books--Science
Classification, Library of Congress
Classification--Books--General works