@article{702319, title = {Bounds for eigenvalues of differential equations}, booktitle = {Equadiff 5}, series = {GDML\_Books}, publisher = {BSB B.G. Teubner Verlagsgesellschaft}, address = {Leipzig}, year = {1982}, pages = {348-351}, zbl = {0527.65072}, url = {http://dml.mathdoc.fr/item/702319} }
Velte, Waldemar. Bounds for eigenvalues of differential equations, dans Equadiff 5, GDML_Books, (1982), pp. 348-351. http://gdmltest.u-ga.fr/item/702319/