Харолд Фостер — разлика између измена

* -{Blackbeard, Bill. "Artist of the Absurd", Tarzan in Color. Vol. 1. 1931–1932 New York: Flying Buttress Classics Library.}-. {{page|year=|id=ISBN 978-1-56163-049-73|pages=}}

* -{Kane, Brian M (2001), Hal Foster: Prince of Illustrators, Vanguard Productions,}-. {{page|year=|id=ISBN 978-1-887591-25-76|pages=}}