@article{GDZPPN00229754X, title = {Absolute Convergence of Eigenfunction Expansions.}, journal = {Mathematische Annalen}, volume = {174}, year = {1967}, pages = {307-314}, zbl = {0145.39701}, url = {http://dml.mathdoc.fr/item/GDZPPN00229754X} }
PEETRE, J. Absolute Convergence of Eigenfunction Expansions.. Mathematische Annalen, Tome 174 (1967) pp. 307-314. http://gdmltest.u-ga.fr/item/GDZPPN00229754X/