1 2 3 4 5 Jimenez, Phil (2008), "Extremists, The", in Dougall, Alastair, The DC Comics Encyclopedia, New York: Dorling Kindersley, p. 117, ISBN 0-7566-4119-5, OCLC 213309017 ↑ Beatty, Scott (2008), "Extreme Justice", in Dougall, Alastair, The DC Comics Encyclopedia, New York: Dorling Kindersley, p. 117, ISBN 0-7566-4119-5, OCLC 213309017 1 2 The Multiversity #1 (2014) ↑ The DC Comics Encyclopedia, Dorling Kindersley Limited, 2004, p. 199, ISBN 0-7566-0592-X