@article{702323,
     title = {About the representation of solutions of linear elliptic equations of arbitrary order},
     booktitle = {Equadiff 5},
     series = {GDML\_Books},
     publisher = {BSB B.G. Teubner Verlagsgesellschaft},
     address = {Leipzig},
     year = {1982},
     pages = {366-369},
     zbl = {0549.35033},
     url = {http://dml.mathdoc.fr/item/702323}
}

Wildenhain, Günther. About the representation of solutions of linear elliptic equations of arbitrary order, dans Equadiff 5, GDML_Books,  (1982), pp. 366-369. http://gdmltest.u-ga.fr/item/702323/