"Knowledge Center". Brighter Thinking. The Neon Group. Retrieved 2012-03-06.
thoughtco.com
These anecdotes and the phrase "liquid fire" are often used in references discussing the first neon tube lights in Los Angeles, but the primary source is not provided. One example of a typical, tertiary reference is Bellis, Mary. "The History of Neon Signs: Georges Claude and Liquid Fire". ThoughtCo.