This Easy Journey to Other Planets (in German), has been in the process so long, it has so many times been reworked, that it's no longer palatable to them (devotees). They don't even read it. They'd rather have the English version: Revision history
Diff selection: Mark the radio buttons of the revisions to compare and hit enter or the button at the bottom.
Legend: (cur) = difference with latest revision, (prev) = difference with preceding revision, m = minor edit.