@article{GDZPPN001170430,
title = {A Basic Theorem in the Computation of Ellipsoidal Error Bounds.},
journal = {Numerische Mathematik},
volume = {19},
year = {1972},
pages = {218-229},
zbl = {0227.65046},
url = {http://dml.mathdoc.fr/item/GDZPPN001170430}
}
Guderley, K.G.; Keller, C.L. A Basic Theorem in the Computation of Ellipsoidal Error Bounds.. Numerische Mathematik, Tome 19 (1972) pp. 218-229. http://gdmltest.u-ga.fr/item/GDZPPN001170430/