06/21/1881 Edison, Thomas Alva -- Legal Statements and Testimony
(Boehm, Ludwig K; Meadowcroft, William Henry) Vacuum and glass bulb
[W100DEB]  National Archives, Washington, D.C.: Records of the Patent and Trademark Office (Record Group 241) -- Patent Interference Files -- Boehm v. Edison -- Preliminary Statement of Edison
[W100DEBB; TAEM 0:0]
Courtesy of the National Archives.