Chapter XXV - XXIX. On systems of simultaneous linear partial differential equations. Homogeneous systems. Partial differential equations of the second Order.
A Treatise on Differential Equations Suppl.-Bd., GDML_Books, (1865), p. 74 / Harvested from
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@article{PPN585192146+DMDLOG_0006,
     title = {Chapter XXV - XXIX. On systems of simultaneous linear partial differential equations. Homogeneous systems. Partial differential equations of the second Order.},
     booktitle = {A Treatise on Differential Equations Suppl.-Bd.},
     series = {GDML\_Books},
     publisher = {Macmillan},
     year = {1865},
     pages = {74},
     url = {http://dml.mathdoc.fr/item/PPN585192146+DMDLOG_0006}
}

 (éd.). Chapter XXV - XXIX. On systems of simultaneous linear partial differential equations. Homogeneous systems. Partial differential equations of the second Order., dans A Treatise on Differential Equations Suppl.-Bd., GDML_Books,  (1865), p. 74. http://gdmltest.u-ga.fr/item/PPN585192146+DMDLOG_0006/