Find out more about the 
GNU Project.
GNU Are working on a GNU OperatingSystem, using TheHurd as the Kernel and using GNU UserSpace utilities
RMS wants you to refer to a Linux distribution as GNU/Linux.
His logic is that "Linux" is a Kernel, and it uses mostly GNU UserSpace utilities. Thus the OperatingSystem as a whole is "GNU/Linux".
If the majority of UserSpace is under a GNU License? or BSD License? or other Licences?, doesn't appear to enter into this dicussion for some reason.
60 pages link to GNU:
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