@article{MM2_1987__59_155258,
     author = {Wolfgang Hensgen},
     title = {Operatoren {H1} ... {X.}},
     journal = {Manuscripta mathematica},
     pages = {399--422},
     year = {1987},
     volume = {59},
     url = {http://geodesic.mathdoc.fr/item/MM2_1987__59_155258/}
}