1. Japan Institute for Labor Policy and Training. 2005. "Nihon no choujikan roudou/fuharai roudou jikan no jitai to jissho bunseki" [Actual Conditions and Empirical Analysis of Japan's Long Working Hours: Uncompensated Working Hours]. Roudou seisaku kenkyu houkokusho 22.
2. Japan Institute for Labor Policy and Training. 2006. "Hatarakikata no genjou to ishiki ni kan suru ankeeto chousa kekka" [Results from Survey of Current Working Styles and Awareness]. Chousa shiriizu 20.
3. Japan Personnel Research Institute. 2005. "Kanri kantokusha no jitai ni kan suru chousa kenkyū houkokusho" [Research Report on Survey Regarding Management and Supervisory Staff].