Reed, C.K. & C.A. Reed (1914). Guide to taxidermy. Worcester, Mass., C.K. Reed. pp. 22–23.
George C. Nonte (1973). Firearms encyclopedia. Harper & Row. p. 76. ISBN978-0-06-013213-2. A shotshell which has been cut partially through forward of the head in hope of reducing shot dispersion.
"Shot spread". International Hunter Education Association. Homestudy.ihea.com. 2002. Archived from the original on July 23, 2016. Retrieved 2010-05-13.
marlinforum.com
Eger, Christopher (28 July 2013). "Marlin 25MG Garden Gun". Marlin Firearms Forum. Outdoor Hub LLC. Archived from the original on 2016-09-18. Retrieved 17 September 2016.
Eger, Christopher (28 July 2013). "Marlin 25MG Garden Gun". Marlin Firearms Forum. Outdoor Hub LLC. Archived from the original on 2016-09-18. Retrieved 17 September 2016.
"Shot spread". International Hunter Education Association. Homestudy.ihea.com. 2002. Archived from the original on July 23, 2016. Retrieved 2010-05-13.