1. 1) Aptitude Test Research Group: "Aptitude Test Q&A (in Japanese)," Japanese Railway Book Corp., 15p., 1983.
2. 2) Souma, N.: "Research on Validity of Uchida-Kraepelin Psychodiagnostic Test with Objective Measure," Railway Labor Science Research (in Japanese), No.16, pp.189-194, 1964.
3. 3) Kashiwagi, S.: "Research on Validity of Uchida-Kraepelin Psychodiagnostic Test with Objective Measure(sequel)," Railway Labor Science Research (in Japanese), No.17, pp.69-74, 1965.
4. 4) Takeuchi, T.: "Railway Accidents and Psychological Aptitude Tests," Railway Labor Science Research (in Japanese), No.29, pp.127-135, 1975.
5. 5) Takeuchi, T.: "Railway Accidents and Psychological Aptitude Tests (2)," Railway Labor Science Research (in Japanese), No.30, pp.219-225, 1976.