Griswold, Ralph E. "A history of the SNOBOL programming languages"

[HOPL I] (1979) SIGPLAN Notices 14(04) April 1979 including The first ACM SIGPLAN conference on History of programming languages (HOPL) Los Angeles, CA, June 1-3, 1978   Ralph E. Griswold

Languages mentioned SNOBOL {1962} String processing language SNOFLEX {1974}