@article{CMUC_1977__18_3_a7,
     author = {Groetsch, Charles W.},
     title = {Sequential regularization of ill-posed problems involving unbounded operators},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {489--498},
     publisher = {mathdoc},
     volume = {18},
     number = {3},
     year = {1977},
     mrnumber = {0494905},
     zbl = {0404.65028},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1977__18_3_a7/}
}