1. McAllester D., Givan R.: Taxonomic syntax for first order inferences. Journal of ACM 40(2), 246–283 (1993)
2. Avron, A., The method of hypersequents in the proof theory of propositional non-classical logics, in W. Hodges et al. (eds.), Logic: Foundations to Applications, Oxford Science Publications, Clarendon Press, Oxford, 1996, pp. 1–32.
3. Buss, S.R. (ed.): Handbook of Proof Theory. Elsevier, Amsterdam (1998)
4. Heeffer A.: Automated Theorem Prover for CL and CLuN Based on the Method of Socratic Proofs. Ghent University, Centre for Logic and Philosophy of Science (2003)
5. Leszczyńska, D., Socratic proofs for some normal modal propositional logics, Logique et Analyse 185–188, 259–285, 2004.