@article{PPN481110151_0003+dmdlog11, title = {Harmonic Differential Operators.}, journal = {Forum mathematicum}, volume = {3}, year = {1991}, pages = {177-204}, zbl = {0719.58040}, url = {http://dml.mathdoc.fr/item/PPN481110151_0003+dmdlog11} }
Schimming, Rainer. Harmonic Differential Operators.. Forum mathematicum, Tome 3 (1991) pp. 177-204. http://gdmltest.u-ga.fr/item/PPN481110151_0003+dmdlog11/