Knapp |
Literatur
Bücher
- Toy Trains of Yesteryear; Carstens Publications Inc 1987
- Early Toy Trains; Eigenverlag 2015
Zeitschriften
- THE BIG FOUR - The First Electric Toy Trains in America (Voltamp, Carlisle & Finch, Howard, Knapp); Train Collectors Quarterly, Vol. 17/3 (July 1971), S. 12-18
- THE BIG FOUR - The First Electric Toy Trains in America (Voltamp, Carlisle & Finch, Howard, Knapp); Train Collectors Quarterly, Vol. 17/4 (October 1971), S. 11-18
- THE BIG FOUR - The First Electric Toy Trains in America (Voltamp, Carlisle & Finch, Howard, Knapp); Train Collectors Quarterly, Vol. 18/1 (January 1972), S. 11-18
- Committee for the Certification of Catalog Reproductions; Train Collectors Quarterly, Vol. 20/3 (Summer 1974), S. 12-14
- Knapp; Train Collectors Quarterly, Vol. 48/2 (April 2002), S. 27
- Knapp; Train Collectors Quarterly, Vol. 48/4 (October 2002), S. 16
- Knapp; Train Collectors Quarterly, Vol. 49/2 (April 2003), S. 16
