@article{05005311, title = {Karamata's characterization theorem, Feller, and regular variation in probability theory.}, journal = {Publications de l'Institut Math\'ematique. Nouvelle S\'erie}, volume = {71(85)}, year = {2002}, pages = {79-89}, doi = {10.2298/PIM0271079S}, zbl = {1088.60008}, language = {en}, url = {http://dml.mathdoc.fr/item/05005311} }
Seneta, E. Karamata's characterization theorem, Feller, and regular variation in probability theory.. Publications de l'Institut Mathématique. Nouvelle Série, Tome 71(85) (2002) pp. 79-89. doi : 10.2298/PIM0271079S. http://gdmltest.u-ga.fr/item/05005311/