Kehr, E. A. (1956). Vatican: The stamps and description of their designs and background prepared especially for stamp collectors. The Washington Press.
Čikaški stil citiranja (17. izdanje)Kehr, Ernest A. Vatican: The Stamps and Description of Their Designs and Background Prepared Especially for Stamp Collectors. Newark, New Jersey: The Washington Press, 1956.
MLA način citiranja (8. izdanje)Kehr, Ernest A. Vatican: The Stamps and Description of Their Designs and Background Prepared Especially for Stamp Collectors. The Washington Press, 1956.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.