It expands prior research on contiguity in two ways.First, unlike other studies, it examines how geographic distance between countries affects cooperation as well as conflict.

• 主要特点有二方面：第一、检验两国之间的距离如何影响合作及冲突，第二、检验两国之间的距离，透过贸易间接效果，如何影响合作及冲突。