@article{DAN_1976_226_4_a12,
     author = {V. M. Fedorov},
     title = {Haken{\textquoteright}s algorithm is primitive recursive},
     journal = {Doklady Akademii Nauk},
     pages = {787--788},
     publisher = {mathdoc},
     volume = {226},
     number = {4},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1976_226_4_a12/}
}