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@article{AIHPA_1989__50_3_309_0, author = {Howland, James S.}, title = {Floquet operators with singular spectrum. {I}}, journal = {Annales de l'I.H.P. Physique th\'eorique}, pages = {309--323}, publisher = {Gauthier-Villars}, volume = {50}, number = {3}, year = {1989}, mrnumber = {1017967}, zbl = {0689.34022}, language = {en}, url = {http://geodesic.mathdoc.fr/item/AIHPA_1989__50_3_309_0/} }
Howland, James S. Floquet operators with singular spectrum. I. Annales de l'I.H.P. Physique théorique, Tome 50 (1989) no. 3, pp. 309-323. http://geodesic.mathdoc.fr/item/AIHPA_1989__50_3_309_0/