@article{MZ_1969__112_171243,
     author = {Paul Schaefer},
     title = {Matrix {Transformations} of {Almost} {Convergent} {Sequences.}},
     journal = {Mathematische Zeitschrift},
     pages = {321--325},
     publisher = {mathdoc},
     volume = {112},
     year = {1969},
     zbl = {0181.33501},
     url = {http://geodesic.mathdoc.fr/item/MZ_1969__112_171243/}
}