In 1980, Tempo books released a series by David Hagberg: Massacre in the 22nd Century, War of the Citadels, Crisis on Citadel II, Forces from the Federation, Citadels under Attack and Citadels on Earth.
בשנת 1980 יצאה סדרה שכללה את הספרים Massacre in the 22nd Century, War of the Citadels, Crisis on Citadel II, Forces from the Federation, Citadels under Attack ו- Citadels on Earth.