@article{05379363,
title = {An admissibility criterion for inference rules with metavariables in the modal logic S4},
journal = {Sibirskij Matematicheskij Zhurnal},
volume = {48},
year = {2007},
pages = {396-407},
zbl = {1164.03303},
language = {en},
url = {http://dml.mathdoc.fr/item/05379363}
}
Rutskij, A.N. An admissibility criterion for inference rules with metavariables in the modal logic S4. Sibirskij Matematicheskij Zhurnal, Tome 48 (2007) pp. 396-407. http://gdmltest.u-ga.fr/item/05379363/