@article{1183743896, author = {Visser, Albert}, title = {An Inside View of Exp; or, The Closed Fragment of the Provability Logic of $I\Delta\_0 + \Omega\_1$ with a Propositional Constant for $\operatorname{Exp}$}, journal = {J. Symbolic Logic}, volume = {57}, number = {1}, year = {1992}, pages = { 131-165}, language = {en}, url = {http://dml.mathdoc.fr/item/1183743896} }
Visser, Albert. An Inside View of Exp; or, The Closed Fragment of the Provability Logic of $I\Delta_0 + \Omega_1$ with a Propositional Constant for $\operatorname{Exp}$. J. Symbolic Logic, Tome 57 (1992) no. 1, pp. 131-165. http://gdmltest.u-ga.fr/item/1183743896/