@article{CMH_1987__62_140075,
     author = {Eugene Trubowitz and John Garnett},
     title = {Gaps and bands of one dimensional periodic {Schr\"odinger} operators, {II.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {18--37},
     publisher = {mathdoc},
     volume = {62},
     year = {1987},
     zbl = {0649.34034},
     url = {http://geodesic.mathdoc.fr/item/CMH_1987__62_140075/}
}