@article{GDZPPN002435438, title = {Unique Normal Forms for Planar Vector Fields.}, journal = {Mathematische Zeitschrift}, volume = {199}, year = {1988}, pages = {303-310}, zbl = {0691.58012}, url = {http://dml.mathdoc.fr/item/GDZPPN002435438} }
Baider, Alberto; Churchill, Richard. Unique Normal Forms for Planar Vector Fields.. Mathematische Zeitschrift, Tome 199 (1988) pp. 303-310. http://gdmltest.u-ga.fr/item/GDZPPN002435438/