@article{ZNSL_1977_68_a8,
     author = {S. V. Pakhomov},
     title = {How to prove that two classes of simple primitive recursive functions are distinct},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {115--122},
     publisher = {mathdoc},
     volume = {68},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1977_68_a8/}
}