1. Francez, N.: Proof-theoretic Semantics. College Publications (2015)
2. Synthese Library;A Klev,2019
3. Klev, A.: Name of the Sinus Function. In: Sedlár, I., Blicha, M. (eds.) The Logica Yearbook 2018. College Publications, London (2019)
4. Martin-Löf, P.: Intuitionistic type theory: Notes by Giovanni Sambin of a series of lectures given in Padua, June 1980. Bibliopolis, Napoli (1984)
5. International Series of Monographs on Computer Science;B Nordström,1990