@article{MABA_1989_3_1_a6,
     author = {M. Dobovishek},
     title = {Quadratic {Equation} in {Unital} {C*} {\textendash} {Algebra}},
     journal = {Mathematica balkanica},
     pages = {61},
     publisher = {mathdoc},
     volume = {3},
     number = {1},
     year = {1989},
     url = {http://geodesic.mathdoc.fr/item/MABA_1989_3_1_a6/}
}