French, J. W. "The Description of Aptitude and Achievement Tests in Terms of Rotated Factors." Psychometric Monographs, No. 5, 1951 .
2.
French, J. W.Manual for Kit of Selected Tests for Reference Aptitude and Achievement Factors. Princeton : Educational Testing Service, 1954 .
3.
Fruchter, B. "Measurement of Spatial Abilities (History and Background)." EDUCATIONAL AND PSYCHOLOGICAL MEASUREMENTXIV ( 1954 ), 387-395.
4.
Guilford, J. P. (Editor) Printed Classification Tests. AAF Aviation Psychology Program Research Reports, No. 5. Washington, D. C.: Government Printing Office, 1947.
5.
Guilford, J. P., Fruchter, B., and Zimmerman, W. S. "Factor Analysis of the Army Air Forces Sheppard Field Battery of Experimental Aptitude Tests." Psychometrika, XVII (1952), 45-68.
6.
Kelley, T. L.Crossroads in the Mind of Man . Stanford, California : Stanford University Press, 1928.
7.
Michael, W. B. "The Nature of Space and Visualization Abilities : Some Recent Findings Based on Factor Analysis Studies." Transactions of the New York Academy of Science, XI (1949), 275-281.
8.
Michael, W. B. "A Suggested Research Approach to the Identification of Psychological Processes Associated with Spatial-Visualization Factors." EDUCATIONAL AND PSYCHOLOGICAL MEASUREMENT, XIV (1954), 401-406.
9.
Michael, W. B., Zimmerman, W. S., and Guilford, J. P. "An Investigation of Two Hypotheses Regarding the Nature of the Spatial-Relations and Visualization Factors." EDUCATIONAL AND PSYCHOLOGICAL MEASUREMENT, X (1950), 187-213.
10.
Michael, W. B., Zimmerman, W. S., and Guilford, J. P. "An Investigation of the Nature of Spatial-Relations and Visualization Factors in Two High School Samples." EDUCATIONAL AND PSYCHOLOGICAL MEASUREMENT, XI (1951), 561-577.
11.
Roff, Merrill. "A Factorial Study of Tests in the Perceptual Area." Psychometric Monographs , No. 8, 1952.
12.
Spearman, C.Abilities of Man. New York: Macmillan and Company . 1927.
13.
Thurstone, L. L.Primary Mental Abilities. Psychometric Monographs, No. I, 1938.
14.
Thurstone, L. L.Individual and Group Tests of Mechanical Aptitude, Report No. 57. Chicago: The University of Chicago, Psychometric Laboratory , 1950.
15.
Thurstone, L. L.Some Primary Mental Abilities in Visual Thinking, Report No. 59. Chicago : The University of Chicago, Psychometric Laboratory , 1950.
16.
Thurstone, L. L.An Analysis of Mechanical Aptitude, Report No. 62. Chicago: The University of Chicago, Psychometric Laboratory, 1951 .
17.
Zimmerman, W. S. "A Revised Orthogonal Rotational Solution for Thurstone's Original Primary Mental Abilities Test Battery ." Psychometrika, XVIII (1953), 77-93.
18.
Zimmerman, W. S. "Hypotheses Concerning the Nature of the Spatial Factors." EDUCATIONAL AND PSYCHOLOGICAL MEASUREMENT, XIV ( 1954 ), 396-400.