There are three books that you can use as a reference for Confederate. If I recall correctly, PMG uses the Friedberg catalog numbering system for Confederate notes, which start with CS-##, and found in "Paper Money of the United States" guide published by Coin & Currency Institute. A second reference book is titled "Confederate States Paper Money" published by Krause Publications. The third book is "Comprehensive Catalog of Confederate Paper Money" published by BNR books. Hope this helps you out.