@article{10_21136_CMJ_1987_102190,
     author = {T\"ollis, Theodore},
     title = {On means of positive definite matrices},
     journal = {Czechoslovak Mathematical Journal},
     pages = {628--641},
     publisher = {mathdoc},
     volume = {37},
     number = {4},
     year = {1987},
     doi = {10.21136/CMJ.1987.102190},
     mrnumber = {913995},
     zbl = {0644.15008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1987.102190/}
}