@article{DM_2000_12_4_a5,
     author = {M. F. Ra\c{t}\u{a} and A. G. Russu},
     title = {On some properties of systems, complete with respect to expressibility, of formulas in the {G\"odel{\textendash}L\"ob} provability logic},
     journal = {Diskretnaya Matematika},
     pages = {63--82},
     year = {2000},
     volume = {12},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_2000_12_4_a5/}
}