Harslem, E. F.; Heafner, J. F.: The ISPL basic file system and file subsystem for support of computing research. Santa Monica, Calif.: The RAND Corp. 1971. (The RAND Corp. R-603-ARPA, August 1971 .)

Languages mentioned

• GRAIL {1967} Flowcharting language based on JOSS
• ISPL {1971} Incremental System Programming Language