"Hiroki Katsumata,Satoshi Tayu","On Three-Directional Orthogonal Ray Cacti","IPSJ SIGAL","IPSJ SIG Technical Report",,"Vol. 2020-AL-3",,,2020,Nov. "Satoshi Tayu","Some Characterizations of Three-Directional Orthogonal Ray Graphs",,"Proceedings of the 2016 IEICE General Conference","Institute of Electronics, Information and Communication Engineers",,"No. A-1-4",,2020,Mar.