@article{MAN_1984__268_182917,
     author = {Hansen S\"onke},
     title = {Singularities of {Transmission} {Problems.}},
     journal = {Mathematische Annalen},
     pages = {233--254},
     year = {1984},
     volume = {268},
     zbl = {0523.58041},
     url = {http://geodesic.mathdoc.fr/item/MAN_1984__268_182917/}
}