@article{10_21136_CMJ_1987_102180,
     author = {Dane\v{s}, Josef},
     title = {The {Hilbert} projective metric and an equation in a $C^\ast$-algebra},
     journal = {Czechoslovak Mathematical Journal},
     pages = {522--532},
     publisher = {mathdoc},
     volume = {37},
     number = {4},
     year = {1987},
     doi = {10.21136/CMJ.1987.102180},
     mrnumber = {913985},
     zbl = {0642.46049},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1987.102180/}
}