Selected references
- Noam Chomsky. On certain formal properties of grammars. Information and Control, 2(2):137-167, June 1959.
- Seymour Ginsburg and H. Gordon Rice. Two families of languages related to ALGOL. Journal of the ACM, 9(3):350-371, July 1962.
- Seymour Ginsburg and Gene F. Rose. Some recursively unsolvable problems in ALGOL-like languages. Journal of the ACM, 10(1):29-47, January 1963.
- Seymour Ginsburg and Edwin H. Spanier. Quotients of context-free languages. Journal of the ACM, 10(4):487-492, October 1963.