APA

U.S. Post Office Dept. Division of Stamps, . (1939). A description of United States postage stamps. Washington: U.S. Govt. Print. Off.

Chicago

U.S. Post Office Dept. Division of Stamps, . 1939. A description of United States postage stamps. Washington: U.S. Govt. Print. Off.

Harvard

U.S. Post Office Dept. Division of Stamps, . (1939). A description of United States postage stamps. Washington: U.S. Govt. Print. Off.

MLA

U.S. Post Office Dept. Division of Stamps, . A description of United States postage stamps. Washington: U.S. Govt. Print. Off. 1939.