Bin Xiong & Zhongyi Zheng;Ruifang Liu;Mingqing Zhai;Yuanqing Lin 
GRAPH THEORY: IN MATHEMATICAL OLYMPIAD AND COMPETITIONS [PDF ebook] 

In 1736, the mathematician Euler invented graph theory while solving the Konigsberg seven-bridge problem. Over 200 years later, graph theory remains the skeleton content of discrete mathematics, which serves as a theoretical basis for computer science and network information science. This book introduces some basic knowledge and the primary methods in graph theory by many interesting problems and games.