Silent Jackpot Bell [War Eagle] © 1931 Mills Novelty.
Machine's picture.
Collector's Treasury of Antique Slot Machines from Contemporary Advertising - Peter Bach - Page 130
For Amusement Only - Thomas Gustwiller - Taylor Printing - 1995 - Page 31
The Coin Machine Journal - January 1940 issue
Loose Change Blue Book for Slot Machines [4th Edition]
Automatic Pleasures - The History of the Coin Machine - Nic Costa - 1988 - Page 98