@article{IM2_1987_28_3_a6,
     author = {V. V. Rybakov},
     title = {Decidability of admissibility in the modal system~$\mathrm{Grz}$ and in intuitionistic logic},
     journal = {Izvestiya. Mathematics },
     pages = {589--608},
     publisher = {mathdoc},
     volume = {28},
     number = {3},
     year = {1987},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1987_28_3_a6/}
}