@article{MZM_2000_67_4_a10,
     author = {A. W. Niukkanen},
     title = {Extending the factorization principle to hypergeometric series of general form},
     journal = {Matemati\v{c}eskie zametki},
     pages = {573--581},
     publisher = {mathdoc},
     volume = {67},
     number = {4},
     year = {2000},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2000_67_4_a10/}
}