Referencoj

• GNU Make Manual

• CVS - Concurrent Versions System
  Tip: To restore from Attic, this seems to be best way: cvs update -p -r N.N foo > foo
  where N.N is penultimate revision (i.e. last real one!). Then cvs add and commit foo.
• Subversion - "a compelling replacement for CVS"
• git - the fast version control system