@article{AIHPA_1998__69_2_265_0,
     author = {Howland, James S.},
     title = {Floquet operators with singular spectrum. {III}},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {265--273},
     publisher = {Gauthier-Villars},
     volume = {69},
     number = {2},
     year = {1998},
     mrnumber = {1638899},
     zbl = {0910.34068},
     language = {en},
     url = {http://archive.numdam.org/item/AIHPA_1998__69_2_265_0/}
}