Cattell, R. B. "Temperament Tests. II. Tests." British Journal of Psychology, XXIV (1933), 20 -49.
2.
Cattell, R. B.Description and Measurement of Personality. Yonkerson-Hudson: World Book Co., 1946.
3.
Kleemeier, L. B. and Kleemeier, R. W. "Effects of Benzedrine Sulfate (Amphetamine) on Psychomotor Performance." American Journal of Psychology, LX (1947), 89-100.
4.
Notcutt, B. "Perseveration and Fluency." British Journal of Psychology, XXXIII (1943), 200 -208.
5.
Spearman, C.The Abilities of Man. New York: Macmillan Co., 1927.
6.
Walker, K. F., Staines, R. G. and Kenna, J. C. "P-Tests and the Concept of Mental Inertia." Character and Personality , XII (1943), 32 -42.
7.
Yerkes, R. M. (ed.) Memoirs of the National Academy of Sciences, XV (1921), 207- 230 .