Robert Arneson Artist Signed Litho. Image of Arneson sitting next to one of his self portrait sculptures. All autographs & signed ephemera presented here is from the Cordelia Platt autograph collection. Highly regarded in the autograph industry, Cordelia was the president of the UACC (United autograph collectors club) and a well known dealer for many years. She was official authenticator of Marilyn Monroe and friend to many artists and cartoonists. American Antique Auctions is proud to present a slice of history with this collection presented without reserve.