@article{NSJOM_1987_17_2a_6,
     author = {{\CYRYA}{\cyra}{\cyrn}{\cyre}{\cyrz} 

 {\CYRU}{\cyrsh}{\cyra}{\cyrn}},
     title = {{\CYRO}{\cyrd}{\cyri}{\cyrn} {\cyrk}{\cyrl}{\cyra}{\cyrs}{\cyrs} 6-{\cyrg}{\cyrr}{\cyru}{\cyrp}{\cyrp}{\cyro}{\cyri}{\cyrd}{\cyro}{\cyrv} {\cyri} 

 {2{\CYRN}-{\cyrg}{\cyre}{\cyro}{\cyrm}{\cyre}{\cyrt}{\cyrr}{\cyri}{\cyri}}},
     journal = {Novi Sad Journal of Mathematics},
     pages = {89-108},
     publisher = {mathdoc},
     volume = {17},
     number = {2},
     year = {1987},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1987_17_2a_6/}
}