1. A final solution to the dangling else of ALGOL 60 and related languages;Abrahams;Comm. ACM,1966
2. Syntax of Programming Languages. Theory and Practice;Backhouse,1979
3. Backus, J.W. [1959]. The syntax and semantics of the proposed international algebraic language of the Zurich ACM-GAMM Conference. Proc. Int. Conf. on Inform. Processing, UNESCO Paris, 1959, 125–132.
4. de Bakker, J.W. [1967]. Formal Definition of Programming Languages, with an Application to the Definition of ALGOL 60. Math. Cent. Tracts 16, Mathematisch Centrum, Amsterdam, 1967.
5. On formal properties of simple phrase structure grammars;Bar-Hillel;Z. Phonetik. Sprach. Komm.,1961