outerplanar graphs外平面图的
outerplanar maps外平面地图
directed outerplanar有向外平面图
maximum outerplanar graph极大外平面图
almost-outerplanar graph几乎外平面图
maximal outerplanar graphs极大外平面图
critical maximal outerplanar graph临界极大外平面图
an open outerplanar开外