@incollection{geronimo:2004:wkb,
    author = {Geronimo, Jeffrey S. and Bruno, Oscar and Van Assche, Walter},
     title = {W{KB} and turning point theory for second-order difference
              equations},
 booktitle = {Spectral Methods for Operators of Mathematical Physics},
    series = {Oper. Theory Adv. Appl.},
    volume = {154},
     pages = {101–138},
 publisher = {Birkh\"auser},
   address = {Basel},
      year = {2004},
   mrclass = {39A10 (33C45 34E20 41A60 65Q05)},
  mrnumber = {2103370 (2005g:39010)},
mrreviewer = {Ioannis K. Purnaras},
     zblno = {1064.39018},
     links = {\URL[FullText]{http://wis.kuleuven.be/analyse/walter/turning.pdf}}}