Washington-Franklin Imperforate Help

I'm looking for internet sources for the production, distribution and use, both Bureau and Private Vendors, of imperforate coil stamps of the U.S. Washington-Franklins issues. I have access to all information on the USSS data base but would like additional sources on this subject for a project I'm working on. I would also like information on both affixing machines and vending machines, and their manufactures/vendors, that used imperforated coil stamps. I appreciate any information that anyone can give me for this request