Ibbs and Tillett: The Rise and Fall of a Musical Empire - Christopher Fifield - Google Books

http://books.google.de/books?id=qz-s4zdLCNsC&pg=PA227&dq=%22Betty+Humby%22&hl=de#v=onepage&q=%22Betty%20Humby%22&f=true

For the greater part of the twentieth century, Ibbs and Tillett's concert agency was to the British music industry what Marks and Spencer is to the world of the department store. The roll-call of famous musicians on its books was unmatched, and included…