@book {IOPORT.00703469,
    author       = {Igoshin, V.I.},
    title        = {Mathematical logic and the theory of algorithms. (Matematicheskaya logika i teoriya algoritmov.)},
    year         = {1991},
    isbn         = {5-292-00259-3},
    pages        = {257~p.},
    publisher    = {Saratov: Izdatel'stvo Saratovskogo Universiteta},
    identifier   = {00703469},
}