1. Think like a Grandmaster. Batsford Press Oxford 1995. Think like a Grandmaster. Batsford Press Oxford 1995.
2. E. R. Brace. An Illustrated Dictionary of Chess pages 310--310. 1977. E. R. Brace. An Illustrated Dictionary of Chess pages 310--310. 1977.
3. THE CHESS QUERY LANGUAGE: CQL
4. S. J. Edwards. Standard: Portable Game Notation Specification and Implementation Guide. S. J. Edwards. Standard: Portable Game Notation Specification and Implementation Guide.