@article{GDZPPN002439131, title = {On the rank of harmonic maps.}, journal = {Mathematische Zeitschrift}, volume = {207}, year = {1991}, pages = {535-538}, zbl = {0717.31006}, url = {http://dml.mathdoc.fr/item/GDZPPN002439131} }
Kazdan, Jerry L.; Jin, Zhiren. On the rank of harmonic maps.. Mathematische Zeitschrift, Tome 207 (1991) pp. 535-538. http://gdmltest.u-ga.fr/item/GDZPPN002439131/