the Edge of Forever. Edgeworth Abbey. 2009. Herbert F. Solow and RobertH. Justman. Inside Star Trek: The Real Story. Pocket Books. 1996. ISBN 0-671-00974-5
Roddenberry: The Myth and the Man Behind Star Trek》;《星際爭霸戰》製作人鮑伯·傑斯特曼(Bob Justman)寫的書;《星際爭霸戰》劇本作者桃樂絲·方塔那(Dorothy C. Fontana)在科幻影集影友會中的談話;以及哈蘭·艾利森(Harlan