Malibu (in their Eternity imprint) put out 2 4-issue Tom Corbet series.
Core currently has each one duplicated, so there are 4 series that should be combined down to 2.
The one just called “Tom Corbett” should be merged to Book one, I’d recommend keeping the 2 fully titled series:
Tom Corbett Space Cadet Book One
Tom Corbett Space Cadet Book Two