Fulton, David L. and Thomas, Richard T. "ABACUS/X an incremental compiler for minicomputer use" pp119-124

[SIGPLAN] (1976) SIGPLAN Notices 11(05) (May 1976)  

Languages mentioned ABACUS 10 {1968} Data General JOSS ABACUS/X {1970} Data General JOSS dialect FOCAL {1968} FOrmula CALculator. - JOSS family