Hutchison, Thomas William; Macy, Amy; Allen, Paul (2006). Record Label Marketing. Taylor & Francis. pp. 3 de 410. ISBN9780240807874. Consultado el 12 de julio de 2021.
The “Sentinel Chromatron” machine for recording on uncoated aluminum is described as part of a History Detectives 2007 investigation of an Amos 'n' Andy Recording (Official PBS transcript here). The Amos 'n' Andy radio episode recorded was called “Breach of Promise”; it was broadcast on March 5, 1931, by the Woodmen of the World on WOW radio in Omaha (Nebraska).