@article{GDZPPN002066386,
title = {Gaps and bands of one dimensional periodic Schr\"odinger operators, II.},
journal = {Commentarii mathematici Helvetici},
volume = {62},
year = {1987},
pages = {18-37},
zbl = {0649.34034},
url = {http://dml.mathdoc.fr/item/GDZPPN002066386}
}
Trubowitz, Eugene; Garnett, John. Gaps and bands of one dimensional periodic Schrödinger operators, II.. Commentarii mathematici Helvetici, Tome 62 (1987) pp. 18-37. http://gdmltest.u-ga.fr/item/GDZPPN002066386/