@article{PORMA_1997__54_4_47925,
     author = {Seyhan, H. and S\"onmez, A.},
     title = {On  summability factors.},
     journal = {Portugaliae mathematica},
     pages = {393--398},
     year = {1997},
     volume = {54},
     number = {4},
     zbl = {0893.40005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1997__54_4_47925/}
}