§ 51. Die elliptischen Differentialgleichungen
Lehrbuch der Algebra Bd. 3, GDML_Books, (1908), p. 166 / Harvested from
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     title = {\S\ 51. Die elliptischen Differentialgleichungen},
     booktitle = {Lehrbuch der Algebra Bd. 3},
     series = {GDML\_Books},
     year = {1908},
     pages = {166},
     url = {http://dml.mathdoc.fr/item/PPN234736674+dmdlog64}
}

 (éd.). § 51. Die elliptischen Differentialgleichungen, dans Lehrbuch der Algebra Bd. 3, GDML_Books,  (1908), p. 166. http://gdmltest.u-ga.fr/item/PPN234736674+dmdlog64/