[PT031AAD], Patent Caveat, Thomas Alva Edison, December 5th, 1888
Cylinder record and duplicating technology
[PT031AAD-F] Patent Series -- Caveat Files
https://edisondigital.rutgers.edu/document/PT031AAD
Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
Archive.org Viewer, Microfilm Series Reel 113