1. Barendregt, H.P.: The type-free lambda-calculus. In: Barwise, J. (ed.) Handbook of Mathematical Logic, vol. 90, pp. 1091–1132. Amsterdam, North Holland (1977)
2. Butler, S. (ed.): Homer, The Iliad, vol. 18. New York and Bombay: Longmans, Green and Co., London (1898)
3. Engeler, E.: Algebras and combinators. Algebra Universalis 13, 389–392 (1981)
4. Fehlmann, T.M., Kranich, E.: A general model for representing knowledge - intelligent systems using concepts (2023, preprint). https://web.tresorit.com/l/mCAQY#ALX3kSa3fAifnE0lB5Na6w. Accessed 16 June 2023
5. Barendregt, H., Barendsen, E.: Introduction to Lambda Calculus. University Nijmegen, Nijmegen (2000)