@article{RSMUP_1978__59__199_0,
     author = {Cellina, Arrigo and Sartori, Caterina},
     title = {The search for fixed points under perturbations},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {199--208},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {59},
     year = {1978},
     mrnumber = {547086},
     zbl = {0424.47041},
     language = {en},
     url = {http://archive.numdam.org/item/RSMUP_1978__59__199_0/}
}