This primary source comes from the Records of the National Archives and Records Administration.
National Archives Identifier:
6922223Full Citation: Chalk Used for Final Polishing and Ink Removal before Printing; 4/13/1976; Records of the National Archives and Records Administration, Record Group 64. [Online Version, https://docsteach.org/documents/document/chalk-used-for-final-polishing-and-ink-removal-before-printing, September 9, 2024]