@article{GDZPPN00235327X, title = {A note on functions with a spectral gap.}, journal = {Mathematica Scandinavica}, volume = {36}, year = {1975}, pages = {280-286}, url = {http://dml.mathdoc.fr/item/GDZPPN00235327X} }
Yatuba, Kozo. A note on functions with a spectral gap.. Mathematica Scandinavica, Tome 36 (1975) pp. 280-286. http://gdmltest.u-ga.fr/item/GDZPPN00235327X/