1. Clark, Edward L. Reliability of college grades. Unpublished paper presented to American Psychological Association in September, 1950.
2. Cureton, Edward E. Reliability of a set of averages of unequal numbers of scores. Unpublished paper read at the March, 1951, meeting of the Southern Society for Philosophy and Psychology.
3. Fisher, R. A. Statistical methods for research workers. (10th Ed.) Edinburgh: Oliver and Boyd, 1946.
4. Gulliksen, Harold. Theory of mental tests. New York: John Wiley and Sons, 1950.
5. Horst, Paul. A generalized expression for the reliability of measures.Psychometrika, 1949,14, 21–31.