@article{M2AN_2013__47_1_305_0,
     author = {Cardone, Giuseppe and Nazarov, Sergei A. and Ruotsalainen, Keijo},
     title = {Bound states of a converging quantum waveguide},
     journal = {ESAIM: Mathematical Modelling and Numerical Analysis },
     pages = {305--315},
     publisher = {EDP-Sciences},
     volume = {47},
     number = {1},
     year = {2013},
     doi = {10.1051/m2an/2012033},
     mrnumber = {2997503},
     language = {en},
     url = {http://archive.numdam.org/articles/10.1051/m2an/2012033/}
}