Algorithmic orbit classification for some Borel group actions

Bürgstein, Hartmut; Hesselink, Wim H.

Compositio Mathematica, Volume 61 (1987) p. 3-41

A classification of the nilpotent triangular matrices

Hesselink, Wim H.

Compositio Mathematica, Volume 55 (1985) p. 89-133