@article{10_4064_sm_96_3_231_236,
     author = {Waldemar Hebisch and Adam Sikora},
     title = {A smooth subadditive homogeneous norm on a homogeneous group},
     journal = {Studia Mathematica},
     pages = {231--236},
     publisher = {mathdoc},
     volume = {96},
     number = {3},
     year = {1990},
     doi = {10.4064/sm-96-3-231-236},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-96-3-231-236/}
}