@article{NSJOM_1977_7_Nonea_4,
     author = {Nikoli\'c-Despotovi\'c Danica},
     title = {On the convergence 

 of the series of rational operators},
     journal = {Novi Sad Journal of Mathematics},
     pages = {29-35},
     publisher = {mathdoc},
     volume = {7},
     year = {1977},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1977_7_Nonea_4/}
}