Frank Spittle (23 July 2008). "Bell Target Story"(PDF). Bell Target Shooting. pp. 2–9. Archived(PDF) from the original on 19 April 2022. Retrieved 28 March 2023.
Frank Spittle (23 July 2008). "Bell Target Story"(PDF). Bell Target Shooting. pp. 2–9. Archived(PDF) from the original on 19 April 2022. Retrieved 28 March 2023.