Manning, Matthew K.; Dolan, Hannah, ed. (2010). «1980s». DC Comics Year By Year A Visual Chronicle. Dorling Kindersley. p. 227. ISBN978-0-7566-6742-9. «Formerly part of the Charlton Comics line, the Question carved his mysterious niche into the DC Universe with the help of writer Dennis O'Neil and artist Denys Cowan.»
