@article{GDZPPN00235098X, title = {On the Fine Structure of Spectra.}, journal = {Mathematica Scandinavica}, volume = {28}, year = {1971}, pages = {37-49}, zbl = {0236.47006}, url = {http://dml.mathdoc.fr/item/GDZPPN00235098X} }
Halberg, C.J.A., Jr.; Samuelsson, A. On the Fine Structure of Spectra.. Mathematica Scandinavica, Tome 28 (1971) pp. 37-49. http://gdmltest.u-ga.fr/item/GDZPPN00235098X/