Adrian Riskin On the nonembeddability and crossing numbers of some toroidal graphs on the Klein bottle. [Citation Graph (0, 0)][DBLP] Discrete Mathematics, 2001, v:234, n:1-3, pp:77-88 [Journal]

Adrian Riskin On the Nonembeddability and Crossing Numbers of Some Kleinical Polyhedral Maps on the Torus. [Citation Graph (0, 0)][DBLP] Graphs and Combinatorics, 2005, v:21, n:1, pp:131-135 [Journal]