1. Indexed Grammars—An Extension of Context-Free Grammars
2. Christopher Bak. 2015. GP 2: efficient implementation of a graph programming language. Ph. D. Dissertation. Department of Computer Science, The University of York. https://etheses.whiterose.ac.uk/12586/
3. Keith L. Clark and Sten-Åke Tärnlund. 1977. A First Order Theory of Data and Programs. In Information Processing, Proceedings of the 7th IFIP Congress. North-Holland Pub. Co., Amsterdam, 939–944.
4. Graph Rewriting: An Algebraic and Logic Approach