I guess everyone in this forum can prove the Theorem
in less than 10 seconds :)) Really want to see
what this guy wrote in his paper.

2000年，侯明辉经过几年的反复推敲和印证，又发现“四边形的外角定理”，即“四边形的两个外角的和等于和它们都不相邻的两个内角的和。”此定理发表在河南《中学生数理化》杂志上。

detail:
http://climate.land.net.cn/mir/21.asp