Martin Göbel Igor N. Nikitin Stanislav V. Klimenko Lialia Nikitina Topological Zoo: Mathematical Visualization in Virtual Environment. 420-426 2001 conf/euromicro/2001 EUROMICRO http://csdl.computer.org/comp/proceedings/euromicro/2001/1236/00/12360420abs.htm db/conf/euromicro/euromicro2001.html#GobelNKN01