@article{GDZPPN002323230, title = {Breaking of Symmetries for Forced Equations.}, journal = {Mathematische Annalen}, volume = {264}, year = {1983}, pages = {473-486}, zbl = {0491.58012}, url = {http://dml.mathdoc.fr/item/GDZPPN002323230} }
Dancer, E.N. Breaking of Symmetries for Forced Equations.. Mathematische Annalen, Tome 264 (1983) pp. 473-486. http://gdmltest.u-ga.fr/item/GDZPPN002323230/