@article{1103940282, author = {Hunziker, W. and Pillet, C.-A.}, title = {Degenerate asymptotic perturbation theory}, journal = {Comm. Math. Phys.}, volume = {88}, number = {2}, year = {1983}, pages = { 219-233}, language = {en}, url = {http://dml.mathdoc.fr/item/1103940282} }
Hunziker, W.; Pillet, C.-A. Degenerate asymptotic perturbation theory. Comm. Math. Phys., Tome 88 (1983) no. 2, pp. 219-233. http://gdmltest.u-ga.fr/item/1103940282/