Jerry Bails et Hames Ware, « Slifer, Roger » [archive du ], Who's Who of American Comic Books 1928-1999, sur Who's Who of American Comic Books 1928-1999,
Jerry Bails et Hames Ware, « Slifer, Roger » [archive du ], Who's Who of American Comic Books 1928-1999, sur Who's Who of American Comic Books 1928-1999,