@article{MZ_1964__84_170274,
     author = {Kazuo Ishiguro},
     title = {On the {Sonnenschein} methods of summability.},
     journal = {Mathematische Zeitschrift},
     pages = {374--377},
     year = {1964},
     volume = {84},
     zbl = {0133.00902},
     url = {http://geodesic.mathdoc.fr/item/MZ_1964__84_170274/}
}