Steven R. Boyd. Patriotic Envelopes of the Civil War: The Iconography of Union and Confederate Covers. Baton Rouge: Louisiana State University Press, 2010.
Civil War Used Patriotics: Featuring the Collection of Professor Jon E. Bischel. (Sale #27; Wednesday-Friday June 21-23 2000) Danbury, CT: Nutmeg Stamp Sales, 2000.
James W. Milgram. Federal Civil War Postal History. Lake Forest, IL: Northbrook Publishing, 2007.
Benjamin Wishnietsky. Confederate Patriotic Covers and Their Usages. North Miami, FL: David G. Phillips Pub. Co., 1991.