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@article{JRAM_1966__223_150754, author = {N.W. Bazley and D.W. Fox}, title = {Comparison operators for lower bounds to {Eigenvalues.}}, journal = {Journal f\"ur die reine und angewandte Mathematik}, pages = {142--149}, publisher = {mathdoc}, volume = {223}, year = {1966}, zbl = {0144.17603}, url = {http://geodesic.mathdoc.fr/item/JRAM_1966__223_150754/} }
N.W. Bazley; D.W. Fox. Comparison operators for lower bounds to Eigenvalues.. Journal für die reine und angewandte Mathematik, Tome 223 (1966), pp. 142-149. http://geodesic.mathdoc.fr/item/JRAM_1966__223_150754/