@incollection{AST_1992__210__303_0,
     author = {Sj\"ostrand, Johannes},
     title = {Exponential convergence of the first eigenvalue divided by the dimension, for certain sequences of {Schr\"odinger} operators},
     booktitle = {M\'ethodes semi-classiques Volume 2 - Colloque international (Nantes, juin 1991)},
     series = {Ast\'erisque},
     pages = {303--326},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {210},
     year = {1992},
     mrnumber = {1221365},
     zbl = {0796.35123},
     language = {en},
     url = {http://archive.numdam.org/item/AST_1992__210__303_0/}
}