@article{MS2_1959__7_165711,
     author = {G.M. Pettersen},
     title = {Summability {Methods} and {Unbounded} {Sequences.}},
     journal = {Mathematica Scandinavica},
     pages = {170--176},
     publisher = {mathdoc},
     volume = {7},
     year = {1959},
     zbl = {0092.05502},
     url = {http://geodesic.mathdoc.fr/item/MS2_1959__7_165711/}
}