Hoppe, Jiri "A comparison of MODULA with other system programming languages" pp129-134

[Proceedings] (1977) Proceedings of the Fifth International Computer Symposium, 1977  

Languages mentioned Concurrent Pascal {1972} Dialect of Pascal which supports monitors CORAL {1963} English military realtime language CS-4 {1975} Intermetrics System Lanugage Modula {1977} Concurrent modular language after Pascal PEARL {1970} Real-Time Language RTL/2 {1972} real-time language based on ALGOL 68