Great Britain. Patent Office. (1869). Patents for inventions: Abridgements of specifications relating to writing instruments and materials. Office of the Commissioners of Patents for Inventions.
Chicago-referens (17:e uppl.)Great Britain. Patent Office. Patents for Inventions: Abridgements of Specifications Relating to Writing Instruments and Materials. Lond.: Office of the Commissioners of Patents for Inventions, 1869.
MLA-referens (8:e uppl.)Great Britain. Patent Office. Patents for Inventions: Abridgements of Specifications Relating to Writing Instruments and Materials. Office of the Commissioners of Patents for Inventions, 1869.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.