1. van Orthogonal design and description of a Formal language;Wijngaarden,1965
2. van Revised report on the algorithmic language ALGOL 68;Wijngaarden;Acta Inform.,1974
3. Grammars for Programming Languages;Cleaveland,1977
4. A sampler of formal definitions;Marcotty;Comput. Surveys,1976
5. Formal Specification of Programming Languages: A Panoramic Primer;Pagan,1981