@article{COCV_2019__25__A40_0, author = {Kao, Chiu-Yen and Osting, Braxton}, title = {Extremal spectral gaps for periodic {Schr\"odinger} operators}, journal = {ESAIM: Control, Optimisation and Calculus of Variations}, publisher = {EDP-Sciences}, volume = {25}, year = {2019}, doi = {10.1051/cocv/2018029}, zbl = {1459.35296}, mrnumber = {4009413}, language = {en}, url = {http://www.numdam.org/articles/10.1051/cocv/2018029/} }