Narasimhan, R. "Syntax-directed interpretation of classes of pictures" pp166-173

[ACM] (1966) [ACM] CACM 9(03) March 1966 includes proceedings of the ACM Programming Languages and Pragmatics Conference, San Dimas, California, August 1965  

Languages mentioned COMPAX {1965} Visual language for the BUBBLE-TALK system PAX {1964} Picture representation language for Cloud Chambers