@misc{10_4153_CMB_1985_030_2,
     title = {Upper {Triangular} {Invariants}},
     journal = {Canadian mathematical bulletin},
     pages = {243--248},
     year = {1985},
     volume = {28},
     number = {2},
     doi = {10.4153/CMB-1985-030-2},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1985-030-2/}
}