Ebeling, D. G. and E. G. Hurst, Jr. "PA3 a general-purpose, time-shared Problem Analysis language"

Proceedings of the Conference on Applications of C (1969) Proceedings of the Conference on Applications of Continuous System Simulation San Franclsco Calif June 1969. New York: ACM 1969  

Languages mentioned PA1 {1967} Problem Analysis Language PA2 {1968} Problem Analysis Language PA3 {1969} Problem Analysis Language