@article{MZM_2014_96_4_a11,
     author = {D. S. Shamkanov},
     title = {Circular {Proofs} for the {G\"odel{\textendash}L\"ob} {Provability} {Logic}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {609--622},
     year = {2014},
     volume = {96},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2014_96_4_a11/}
}