@article{1183524270,
author = {Block, H. D. and Fuchs, W. H. J.},
title = {An enclosure theorem for eigenvalues},
journal = {Bull. Amer. Math. Soc.},
volume = {67},
number = {6},
year = {1961},
pages = { 425-426},
language = {en},
url = {http://dml.mathdoc.fr/item/1183524270}
}
Block, H. D.; Fuchs, W. H. J. An enclosure theorem for eigenvalues. Bull. Amer. Math. Soc., Tome 67 (1961) no. 6, pp. 425-426. http://gdmltest.u-ga.fr/item/1183524270/