[Quellen Beitragsbild: writerswrite u. mycast.io]
Ressourcen
Part #1: https://archive.org/details/1965-12_IF/page/n7/mode/2up
Part #2: https://archive.org/details/1966-01_IF_modified/page/n13/mode/2up
Part #3: https://archive.org/details/1966-02_IF/page/n101/mode/2up
Part #4: https://archive.org/details/1966-04_IF/page/n91/mode/2up
Part #5: https://archive.org/details/1966-03_IF/page/n109/mode/2up
Inhaltsangabe (wikipedia) [engl.] [dt.]
Robert A. Heinlein (wikipedia) [engl.] [dt.]