@article{CMUC_1989_30_3_a2,
     author = {Chiappinelli, Raffaele},
     title = {Estimates on the eigenvalues for some nonlinear ordinary differential operators},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {441--446},
     year = {1989},
     volume = {30},
     number = {3},
     mrnumber = {1031861},
     zbl = {0689.34019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1989_30_3_a2/}
}