@article{ASNSP_1973_3_27_1_53_0,
     author = {Fu\v{c}ik, S. and Ne\v{c}as, J. and Sou\v{c}ek, J. and Sou\v{c}ek, V.},
     title = {Upper bound for the number of eigenvalues for nonlinear operators},
     journal = {Annali della Scuola Normale Superiore di Pisa - Scienze Fisiche e Matematiche},
     pages = {53--71},
     publisher = {Scuola normale superiore},
     volume = {Ser. 3, 27},
     number = {1},
     year = {1973},
     mrnumber = {372918},
     zbl = {0263.58007},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1973_3_27_1_53_0/}
}