@article{SMJ2_2001_27_3_a0,
     author = {Zagorodniuk, S.},
     title = {Analog of {Favard's} {Theorem} for {Polynomials} {Connected} with {Difference} {Equation} of 4-th {Order}},
     journal = {Serdica Mathematical Journal},
     pages = {193--202},
     publisher = {mathdoc},
     volume = {27},
     number = {3},
     year = {2001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SMJ2_2001_27_3_a0/}
}