Michael Rathjen. The Higher Infinite in Proof Theory. In Johann A. Makowsky, Elena V. Ravve, editors, Proceedings of the Annual European Summer Meeting of the Association of Symbolic Logic, Logic Colloquium 1995, Haifa, Israel, August 9-18, 1995. Volume 11 of Lecture Notes in Logic, pages 275-304, Springer, 1995. [doi]
Abstract is missing.