1. S. Bird and P. Blackburn, 1991, A Logical Approach to Arabic Phonology, in Proceedings of the 5th Conference of the European Chapter of the Association for Computational Linguistics, Berlin.
2. P. Blackburn, 1989, Nominal Tense Logic, to appear in Notre Dame Journal of Formal Logic.
3. P. Blackburn, 1990, Nominal Tense Logic and other Sorted Intensional Frameworks, PhD Thesis, Centre for Cognitive Science, University of Edinburgh, Scotland.
4. P. Blackburn and E. Spaan, 1992, A Modal Perspective on the Computational Complexity of Attribute Value Grammar, to appear in Journal of Logic, Language and Information.
5. R. Bull, 1968, An Approach to Tense Logic, Theoria, 12, pages 171–182.