[PT031AAE], Patent Caveat, Thomas Alva Edison, March 22nd, 1889
Date of executed caveat; original draft is PT031AAE1 890203
Cylinder record and duplicating technology
[PT031AAE-F] Patent Series -- Caveat Files
https://edisondigital.rutgers.edu/document/PT031AAE
Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
Archive.org Viewer, Microfilm Series Reel 113