On the recognition of bipolarizable and P 4 -simplicial graphs. Nikolopoulos, Stavros D.; Palios, Leonidas — 2005 Discrete Mathematics and Theoretical Computer Science. DMTCS [electronic only]
Recognizing HH-free, HHD-free, and Welsh-Powell opposition graphs. Nikolopoulos, Stavros D.; Palios, Leonidas — 2006 Discrete Mathematics and Theoretical Computer Science. DMTCS [electronic only]