@article{10_21136_MB_1999_126246, author = {Appell, J\"urgen}, title = {Ein {\quotedblbase}merkw\"urdiges{\textquotedblright} {Spektrum} f\"ur nichtlineare {Operatoren}}, journal = {Mathematica Bohemica}, pages = {221--229}, publisher = {mathdoc}, volume = {124}, number = {2-3}, year = {1999}, doi = {10.21136/MB.1999.126246}, mrnumber = {1780693}, zbl = {0940.47053}, language = {ge}, url = {http://geodesic.mathdoc.fr/articles/10.21136/MB.1999.126246/} }