APA Citation

(1961). Postal zone directory, Philadelphia, Pa. Washington, D.C.: U.S. Post Office Dept..

Chicago Style Citation

Postal Zone Directory, Philadelphia, Pa. Washington, D.C.: U.S. Post Office Dept., 1961.

MLA Citation

Postal Zone Directory, Philadelphia, Pa. Washington, D.C.: U.S. Post Office Dept., 1961.

Warning: These citations may not always be 100% accurate.