McAvennie, Michael; Dolan, Hannah, ed. (2010). „1970s“, DC Comics Year By Year A Visual Chronicle. Dorling Kindersley, გვ. 145. ISBN978-0-7566-6742-9. „Writer Denny O'Neil once stated that he and artist Neal Adams 'set out to consciously and deliberately to create a villain...so exotic and mysterious that neither we nor Batman were sure what to expect.' Who they came up with was arguably Batman's most cunning adversary: the global eco-terrorist named Ra's al Ghul.“
