1. Boyer, R. and Moore, J.: 1979, A Computational Logic, Academic, New York (Harcourt Brace Jovanovich, ACM Monograph Series).
2. Huet, G.: 1973, The undecidability of unification in third order logic, Information and Control 22(3), 257–267.
3. Kalman, J.: 2001, Automated Reasoning with Otter, Rinton, Princeton, NJ.
4. Kohlhase, M.: 1998, Higher-order automated theorem proving, in Automated Deduction – A Basis for Applications, vol. I, vol. 8 of Applied Logic Series, Kluwer, Dordrecht, pp. 431–462.
5. Kowalski, R.: 1970, The case for using equality axioms in automatic demonstration, in Symposium on Automatic Demonstration (Versailles, 1968), Lecture Notes in Mathematics, vol. 125, Springer, Berlin Heidelberg New York, pp. 112–127.