"The Silent Avenger", Variety, August 17, 1927, p. 25. Internet Archive. Retrieved February 28, 2020.
"Inside Stuff—Pictures", Variety (New York, N.Y.), April, 1, 1925, p. 51. Internet Archive. Retrieved February 23, 2020.
"Wolf Fangs", Exhibitors Herald and Moving Picture World, December 8, 1928, p. 68. Internet Archive. Retrieved March 16, 2020.
Rosenwald, Arnold (1929). "The Shepherd Dog Club of the West", The Shepherd Dog Review (Boston, Massachusetts), May 1929, p. 45. Internet Archive. Retrieved March 15, 2020.
Some film references misidentify the star of The Silent Avenger as "Ranger the Dog" cast as "Thunder". Refer for example to Internet Movie Database (IMDb), Amazon, Seattle, Washington. Retrieved March 5, 2020.
"(Beneva) Tillo von Riedekenburg", AKC 369953 (German registry SZ 138465), Pedigree Database, Olafur Tryggvason, Kópavogur, Iceland. Retrieved March 21, 2020. Note that this database, the more reliable source, spells Thunder's registered name "Riedekenburg" not "Riedekenberg" as cited in Motion Picture News.