1.

Barbanera F., and S. Berardi, “Witness Extraction in Classical Logic through Normalization,” pp. 219–246 in Logical Environments, edited by G. Huet and G. Plotkin, Cambridge University Press, Cambridge, 1993. MR 1255117 Barbanera F., and S. Berardi, “Witness Extraction in Classical Logic through Normalization,” pp. 219–246 in Logical Environments, edited by G. Huet and G. Plotkin, Cambridge University Press, Cambridge, 1993. MR 1255117

2.

Barbanera, F., and S. Berardi, “A constructive valuation interpretation for classical logic and its use in witness extraction,” pp. 1–23 in Proceedings of Colloquium on Trees in Algebra and Programming (CAAP), LNCS 581, Springer-Verlag, New York, 1992. MR 94h:03115 Barbanera, F., and S. Berardi, “A constructive valuation interpretation for classical logic and its use in witness extraction,” pp. 1–23 in Proceedings of Colloquium on Trees in Algebra and Programming (CAAP), LNCS 581, Springer-Verlag, New York, 1992. MR 94h:03115

3.

Friedman, H., “Classically and intuitionistically provably recursive functions,” pp. 21–28 in Higher Set Theory, edited by D. S. Scott and G. H. Muller, Lecture Notes in Mathematics, vol. 699, Springer-Verlag, New York, 1978. Zbl 0396.03045 MR 80b:03093 Friedman, H., “Classically and intuitionistically provably recursive functions,” pp. 21–28 in Higher Set Theory, edited by D. S. Scott and G. H. Muller, Lecture Notes in Mathematics, vol. 699, Springer-Verlag, New York, 1978. Zbl 0396.03045 MR 80b:03093

4.

Heyting, A., Mathematische Grundlagenforschung. Intuitionismus. Beweistheorie, Springer, Berlin, Reprinted 1974. Zbl 0278.02002 MR 49:8806  0278.02002 Heyting, A., Mathematische Grundlagenforschung. Intuitionismus. Beweistheorie, Springer, Berlin, Reprinted 1974. Zbl 0278.02002 MR 49:8806  0278.02002

5.

Kreisel, G., “Mathematical significance of consistency proofs,” The Journal of Symbolic Logic, vol. 23 (1958), pp. 155–182. Zbl 0088.01502 MR 22:6710 Kreisel, G., “Mathematical significance of consistency proofs,” The Journal of Symbolic Logic, vol. 23 (1958), pp. 155–182. Zbl 0088.01502 MR 22:6710

6.

Kolmogorov, A. N., “Zur Deutung der Intuitionistischen Logik,” Mathematische Zeitschrift, vol. 35 (1932), pp. 58–56. Zbl 0004.00201 Kolmogorov, A. N., “Zur Deutung der Intuitionistischen Logik,” Mathematische Zeitschrift, vol. 35 (1932), pp. 58–56. Zbl 0004.00201

7.

Martin-Löf, P., “An intuitionistic theory of types: predicative part,” pp. 73–118 in Logic Colloquium 73, edited by H. E. Rose and J. C. Sheperdson, North-Holland, Amsterdam, 1975. Zbl 0334.02016 MR 52:7856 Martin-Löf, P., “An intuitionistic theory of types: predicative part,” pp. 73–118 in Logic Colloquium 73, edited by H. E. Rose and J. C. Sheperdson, North-Holland, Amsterdam, 1975. Zbl 0334.02016 MR 52:7856

8.

Prawitz, D., Natural deduction, a proof theoretical study, Almqvist and Winskell, Stockholm, 1965. Zbl 0173.00205 MR 33:1227  0173.00205 Prawitz, D., Natural deduction, a proof theoretical study, Almqvist and Winskell, Stockholm, 1965. Zbl 0173.00205 MR 33:1227  0173.00205

9.

Prawitz, D., “Validity and normalizability of proofs in first and second order classical and intuitionistic logic,” pp. 11–36 in Atti del I Congresso Italiano di Logica, Bibliopolis, Napoli, 1981. Prawitz, D., “Validity and normalizability of proofs in first and second order classical and intuitionistic logic,” pp. 11–36 in Atti del I Congresso Italiano di Logica, Bibliopolis, Napoli, 1981.

10.

Shoenfield, J. R., Mathematical Logic, Addison-Wesley, Reading, 1967. Zbl 0155.01102 MR 37:1224 Shoenfield, J. R., Mathematical Logic, Addison-Wesley, Reading, 1967. Zbl 0155.01102 MR 37:1224