Callahan, Timothy; Chad Nevett (August 29, 2008). "Final Crisis: Superman Beyond #1: The What is the Space What Now?". The Splash Page. Sequart Research & Literacy Organization. Archived from the original on August 30, 2009. Retrieved September 3, 2008. Callahan, Timothy (May 2007). Grant Morrison: The Early Years. Sequart Journal #1. Sequart.com Books. p. 112. ISBN978-0-615-14087-2. Archived from the original on April 1, 2024. Retrieved September 3, 2008. "Comic Book Limbo, as a metaphorical idea, has been around as long as comic books have been around. Any character who has not appeared for a while could be said to exist in 'Comic Book Limbo'. Morrison takes that concept and turns it into an actual place."
Callahan, Timothy; Chad Nevett (August 29, 2008). "Final Crisis: Superman Beyond #1: The What is the Space What Now?". The Splash Page. Sequart Research & Literacy Organization. Archived from the original on August 30, 2009. Retrieved September 3, 2008. Callahan, Timothy (May 2007). Grant Morrison: The Early Years. Sequart Journal #1. Sequart.com Books. p. 112. ISBN978-0-615-14087-2. Archived from the original on April 1, 2024. Retrieved September 3, 2008. "Comic Book Limbo, as a metaphorical idea, has been around as long as comic books have been around. Any character who has not appeared for a while could be said to exist in 'Comic Book Limbo'. Morrison takes that concept and turns it into an actual place."
Paggi, David; Phegley, Kiel; Taylor, Robert (May 2, 2007). "'52' Roundup". Wizarduniverse.com. Archived from the original on October 11, 2007. Retrieved December 2, 2007.
The same list was published in two places: at Newsarama.com on November 26, 2007, [1],[dead link] and in the "DC Nation" editor's note page at the end of Countdown #22 (November 28, 2007).
Callahan, Timothy; Chad Nevett (August 29, 2008). "Final Crisis: Superman Beyond #1: The What is the Space What Now?". The Splash Page. Sequart Research & Literacy Organization. Archived from the original on August 30, 2009. Retrieved September 3, 2008. Callahan, Timothy (May 2007). Grant Morrison: The Early Years. Sequart Journal #1. Sequart.com Books. p. 112. ISBN978-0-615-14087-2. Archived from the original on April 1, 2024. Retrieved September 3, 2008. "Comic Book Limbo, as a metaphorical idea, has been around as long as comic books have been around. Any character who has not appeared for a while could be said to exist in 'Comic Book Limbo'. Morrison takes that concept and turns it into an actual place."
Paggi, David; Phegley, Kiel; Taylor, Robert (May 2, 2007). "'52' Roundup". Wizarduniverse.com. Archived from the original on October 11, 2007. Retrieved December 2, 2007.