Brain World
Mack Reynolds
United Planets (7)
Section G: United Planets
United Planets (6)
Amazon Planet
United Planets (5)
Code Duello
United Planets (4)
The Rival Rigelians
United Planets (3)
Dawnman Planet
United Planets (2)
Adaptation
United Planets (1)
Planetary Agent X
The Rival Rigelians and Planetary Agent X