@article{RCM_1991__25_1-4_181844,
     author = {S. P. Singh and A. S. Ranadive},
     title = {On the degree of approximation by positive linear operators using the {B-summability} method},
     journal = {Revista colombiana de matematicas},
     pages = {1--10},
     publisher = {mathdoc},
     volume = {25},
     number = {1-4},
     year = {1991},
     zbl = {0772.41023},
     url = {http://geodesic.mathdoc.fr/item/RCM_1991__25_1-4_181844/}
}