Library of Congress
Loc: American Memory: The American Variety Stage Audio Sampler
Information from the Library of Congress on variety show entertainment, 1870-1920 in which students can actually listen to audio samplers of variety entertainment dating from 1913.
Other
Museum of Broadcast Communications: Ed Sullivan Show
An article discussing the history of the Ed Sullivan show.
Other
Museum of Broadcast Communications: Ed Sullivan
Article provides a very thorough review of the life of variety show host Ed Sullivan (1902-1974 CE).