This primary source comes from the Records of the Patent and Trademark Office.
National Archives Identifier:
302052Full Citation: Alexander Graham Bell's Telephone Patent Drawing and Oath; 3/7/1876; Records of the Patent and Trademark Office, Record Group 241. [Online Version, https://www.docsteach.org/documents/document/alexander-graham-bells-telephone-patent-drawing-and-oath, March 28, 2024]