United States. Library of Congress. (1990). Library of Congress classification schedules combined with additions and changes through 1989: Class P, subclasses PL-PM, languages of Eastern Asia, Africa, Oceania, Hyperborean, Indian, and artificial languages. Gale Research.
Citace podle Chicago (17th ed.)United States. Library of Congress. Library of Congress Classification Schedules Combined with Additions and Changes Through 1989: Class P, Subclasses PL-PM, Languages of Eastern Asia, Africa, Oceania, Hyperborean, Indian, and Artificial Languages. Detroit: Gale Research, 1990.
Citace podle MLA (9th ed.)United States. Library of Congress. Library of Congress Classification Schedules Combined with Additions and Changes Through 1989: Class P, Subclasses PL-PM, Languages of Eastern Asia, Africa, Oceania, Hyperborean, Indian, and Artificial Languages. Gale Research, 1990.