Episode 11 of The Trigan Empire
The Three Aliens
aka The Luminous Spheres
The Alien Invasion (The Collection)
De lichtende bollen (Dutch title)
The Luminous Orbs (Dutch title, translated)
A Tale of Invasion (Hawk reprint)
Written by Mike Butterworth
Illustrated by Don Lawrence
The Three Aliens was originally published in 7 instalments in issues 291 (12 August 1967) to 297 (23 September 1967) of Look and Learn magazine.
It was reprinted in 1975 in Vulcan comic.
It was reprinted in 1989 as A Tale of Invasion in Tales from the Trigan Empire (Hawk).
It is reprinted in Volume 3 of The Trigan Empire—The Collection (the Don Lawrence Collection).
It is reprinted in Volume 1 of The Rise and Fall of the Trigan Empire (Rebellion).
Plot summary (Dutch)
MediaFire via British Comics Compilations