@article{MS2_1969__25_166111,
     author = {M. Giertz},
     title = {A {Note} on a {Problem} of {Busemann.}},
     journal = {Mathematica Scandinavica},
     pages = {145--148},
     publisher = {mathdoc},
     volume = {25},
     year = {1969},
     zbl = {0189.22902},
     url = {http://geodesic.mathdoc.fr/item/MS2_1969__25_166111/}
}