@article{1103034174, author = {Beckenbach, E. F.}, title = {Superadditivity inequalities.}, journal = {Pacific J. Math.}, volume = {14}, number = {4}, year = {1964}, pages = { 421-438}, language = {en}, url = {http://dml.mathdoc.fr/item/1103034174} }
Beckenbach, E. F. Superadditivity inequalities.. Pacific J. Math., Tome 14 (1964) no. 4, pp. 421-438. http://gdmltest.u-ga.fr/item/1103034174/