Robert Pollack. On Extensibility of Proof Checkers. In Peter Dybjer, Bengt Nordström, Jan M. Smith, editors, Types for Proofs and Programs, International Workshop TYPES 94, Båstad, Sweden, June 6-10, 1994, Selected Papers. Volume 996 of Lecture Notes in Computer Science, pages 140-161, Springer, 1994.
Abstract is missing.