@article{AL_2016_55_4_a1,
     author = {G. V. Bokov},
     title = {Undecidable iterative propositional calculus},
     journal = {Algebra i logika},
     pages = {419--431},
     publisher = {mathdoc},
     volume = {55},
     number = {4},
     year = {2016},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2016_55_4_a1/}
}