@article{RSMUP_1975__53__15_0,
     author = {Iseki, Kiyoshi},
     title = {Multi-valued contraction mappings in complete metric spaces},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {15--19},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {53},
     year = {1975},
     mrnumber = {410715},
     zbl = {0328.54030},
     language = {en},
     url = {http://archive.numdam.org/item/RSMUP_1975__53__15_0/}
}