On strong reality of the unipotent Lie-type subgroups over a field of characteristic 2. Gazdanova, M.A.; Nuzhin, Ya.N. — 2006 Sibirskij Matematicheskij Zhurnal
Intermediate subgroups of the Steinberg groups over the field of fractions of a principal ideal ring. Moiseenkova, T.V.; Nuzhin, Ya.N. — 2010 Vladikavkazskiĭ Matematicheskiĭ Zhurnal