@article{TRSPY_1967_93_a3,
     author = {Yu. V. Matiyasevich},
     title = {Simple examples of unsolvable canonical calculi},
     journal = {Informatics and Automation},
     pages = {50--88},
     publisher = {mathdoc},
     volume = {93},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1967_93_a3/}
}