Library of Congress. Subject Cataloging Division, Gale Research Company, Koenig, W. F., Martel, C., & Perley, C. W. (1933). Classification. Class P, PB-PH: Philology, modern European languages. Printed as manuscript. U. S. Government Printing Office.
Παραπομπή σε μορφή Chicago (17η εκδ.)Library of Congress. Subject Cataloging Division, Gale Research Company, Walther Frederick Koenig, Charles Martel, και Clarence W. Perley. Classification. Class P, PB-PH: Philology, Modern European Languages. Printed as Manuscript. Washington: U. S. Government Printing Office, 1933.
Παραπομπή σε μορφή MLA (9th εκδ.)Library of Congress. Subject Cataloging Division, et al. Classification. Class P, PB-PH: Philology, Modern European Languages. Printed as Manuscript. U. S. Government Printing Office, 1933.