The Focus Number System. - Samuel C. Lee; Albert D. Edgar (IEEE Trans. Computers, 1977)

Focus software. - Albert D. Edgar; Samuel C. Lee (COMPSAC, 1979)

FOCUS Microcomputer Number System. - Albert D. Edgar; Samuel C. Lee (Commun. ACM, 1979)

Addendum to "The Focus Number System". - Samuel C. Lee; Albert D. Edgar (IEEE Trans. Computers, 1979)