@article{MM2_1983__44_154956,
     author = {K.-H. F\"orster and E.-O. Liebetrau},
     title = {Semi-Fredholm {Operators} and {Sequence} {Conditions.}},
     journal = {Manuscripta mathematica},
     pages = {35--44},
     publisher = {mathdoc},
     volume = {44},
     year = {1983},
     zbl = {0519.47009},
     url = {http://geodesic.mathdoc.fr/item/MM2_1983__44_154956/}
}