outer planar graph meaning in Chinese

外部平面图
外平面图

On the total coloring of a special double - outer planar graph
一个特殊的双外平面图的全染色
The total chromatic number and properties of similar outer planar graphs
类平面图的结构性质与边面全染色
Maximal outer planar graph and perfect matching in the treelike triangular lattice and the treelike polyminoes
极大外平面图与树状三角系统和四角系统的完美匹配