@article{BSMF_1990__118_1_27_0,
     author = {G\'erard, Christian},
     title = {Resonance theory for periodic {Schr\"odinger} operators},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     pages = {27--54},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {118},
     number = {1},
     year = {1990},
     doi = {10.24033/bsmf.2134},
     mrnumber = {91h:35231},
     zbl = {0723.35059},
     language = {en},
     url = {http://www.numdam.org/articles/10.24033/bsmf.2134/}
}