@incollection{JEDP_1987____A6_0,
     author = {Helffer, Bernard and Sj\"ostrand, Johannes},
     title = {\'Equation de {Schr\"odinger} avec champ magn\'etique et \'equation de {Harper}},
     booktitle = {},
     series = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     eid = {6},
     pages = {1--9},
     publisher = {Ecole polytechnique},
     year = {1987},
     language = {fr},
     url = {http://archive.numdam.org/item/JEDP_1987____A6_0/}
}