1. M. A. Abashidze, Ordinal completeness of the Gödel-Löb modal system [in Russian], In: Intensional Logics and Logical Structure of Theories: Material from the Fourth Soviet-Finnish Symposium on Logic, Telavi, May 20–24, 1985, Tbilisi, Metsniereba, 1988, pp. 49–73.
2. S. Abramsky, Algorithmic game semantics. A tutorial introduction, In: H. Schwichtenberg (ed.) et al, Proof and System-Reliability. Proc. NATO Advanced Study Institute, Marktoberdorf, Germany, July 24–August 5, 2001, Dordrecht, Kluwer Academic Publishers, 2002, pp. 21–47.
3. S. Artemov, Explicit provability and constructive semantics, Bull. Symbolic Log. 7 (2001), no. 1, 1–36.
4. S. N. Artemov, Applications of modal logic in proof theory [in Russian], In: Questions of Cybernetics: Nonclassical Logics and Their Applications, Moscow, Nauka, 1982, pp. 3–20.
5. S. N. Artemov and L. D. Beklemishev, On propositional quantifiers in provability logic, Notre Dame J. Formal Logic 34 (1993), no. 3, 401–419.