National Park Service popular study series.
History.

APA Citation

United States. National Park Service. (1941). National Park Service popular study series. [Washington, D.C.]: United States Dept. of the Interior, National Park Service; [for sale by Supt. of Docs., G.P.O.].

MLA Citation

United States. National Park Service. National Park Service Popular Study Series. [Washington, D.C.]: United States Dept. of the Interior, National Park Service; [for sale by Supt. of Docs., G.P.O.], 1941.

Warning: These citations may not always be complete (especially for serials).