@article{MAN_1959__137_160693,
     author = {SIDNEY F. MACK},
     title = {Discontinuities of {Second} {Derivatives} of {Single-Layer} {Potentials.}},
     journal = {Mathematische Annalen},
     pages = {417--426},
     year = {1959},
     volume = {137},
     zbl = {0087.09604},
     url = {http://geodesic.mathdoc.fr/item/MAN_1959__137_160693/}
}