The Prexies by Roland Rustad.
The complete work on the Presidential Series of 1938, Profusely illustrated, covering stamp design, production, rates and usages for each stamp. 343 pages (1994), Paperbound.
Visit US Stamp Society for ordering details.
The Transports by G. H. Davis.
A thorough study of the 1941-44 Transport Airmail stamp issue, discussing historical context, stamp design and development, production data, examples of usages, rates and routes during The Transport Era. 231 pages, Paperbound.
Visit US Stamp Society for ordering details.
Encylopedia of United States Stamps and Stamp Collecting, edited by Rodney A. Juell & Steven J. Rod.
Introduces the reader to the full scope of United States stamps and stamp collecting from stampless covers through the early 21st century. Includes the history of the Postal Service and the various stamp printers, including the Bureau of Engraving and Printing. 730 pages, Hardbound.
Visit US Stamp Society for ordering details.
EXHIBITS
The US Stamp Society has an exhibit photocopy service. Some of these are Prexie-Era related. For more info visit their site.
Usages of the Presidential Issue of 1938, Leonard Piszkiewicz, 160 pages, $15.00 unbound, $17.50 w/binding
The Prexies at Work (remounted 2003), Jeffrey Shapiro, 142 pages, $14.00 unbound, $17.00 w/binding
USSS RESEARCH PAPERS
The US Stamp Society also has these available. Here are the ones related to the Prexie-Era.
#4 1/2c Presidential Bureau Precancels. Plate Numbers and Positions, $4