Pipeless Organ Turns Electricity Into Music, in Popular Mechanics, September 1931, p. 374. — article on Rangertone, an early all-electric tonewheel organ between Telharmonium and Hammond organ
The Robb Wave Organ, su sciencetech.technomuses.ca, Canada Science and Technology Museum. URL consultato il 20 giugno 2015 (archiviato dall'url originale il 3 ottobre 2012).