@article{GDZPPN002095076, title = {Rigidity of Certain Harmonic Mappings.}, journal = {Inventiones mathematicae}, volume = {55}, year = {1979}, pages = {297-307}, zbl = {0418.31005}, url = {http://dml.mathdoc.fr/item/GDZPPN002095076} }
Sunada, Toshikazu. Rigidity of Certain Harmonic Mappings.. Inventiones mathematicae, Tome 55 (1979) pp. 297-307. http://gdmltest.u-ga.fr/item/GDZPPN002095076/