@article{MASLO_1988_38_4_a13,
     author = {Argyros, Ioannis K.},
     title = {Some sufficient conditions for finding a second solution of the quadratic equation in a {Banach} space},
     journal = {Mathematica slovaca},
     pages = {403--408},
     year = {1988},
     volume = {38},
     number = {4},
     mrnumber = {978771},
     zbl = {0681.47030},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MASLO_1988_38_4_a13/}
}