1. Ten years after the bus deregulation in Japan: Toward an evaluation of the abolition of demand-supply balancing;Takahashi;Shoukei Gakusou,2011
2. The Japan Times, Bus Crash in Gunma Leaves Seven Dead, 39 Injuredhttps://www.japantimes.co.jp/news/2012/04/30/national/bus-crash-in-gunma-leaves-seven-dead-39-injured/#.Xrs_SWgzbD4
3. The Japan Times, Overnight Bus Crashes in Karuizawa, Killing 14https://www.japantimes.co.jp/news/2016/01/15/national/night-ski-bus-flips-karuizawa-three-killed-11-critical-condition/#.XrtCAWgzbD4