@article{1102945102, author = {Helton, Jon C.}, title = {Bounds for products of interval functions.}, journal = {Pacific J. Math.}, volume = {49}, number = {2}, year = {1973}, pages = { 377-389}, language = {en}, url = {http://dml.mathdoc.fr/item/1102945102} }
Helton, Jon C. Bounds for products of interval functions.. Pacific J. Math., Tome 49 (1973) no. 2, pp. 377-389. http://gdmltest.u-ga.fr/item/1102945102/