@article{NSJOM_1981_11_Nonea_14,
     author = {Surla 

 Katarina},
     title = {On a 

 posteriori error estimation in solving some classes of operators uquations},
     journal = {Novi Sad Journal of Mathematics},
     pages = {149-159},
     publisher = {mathdoc},
     volume = {11},
     year = {1981},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1981_11_Nonea_14/}
}