Obtaining Comparable Scores on two or More Tests

Flanagan, J. C. "Units, Scores, and Norms ." In E.F. Lindquist (Editor), Educational Measurement. Washington, D. C.: American Council on Education, 1950.

Guilliksen, Harold. Theory of Mental Tests . New York: John Wiley and Sons , 1950.

Karon, Bertram P. "The Stability of Equated Test Scores." Research Bulletin. Princeton : Educational Testing Service, 1955 .

Lord, Frederic M. "Equating Test Scores—A Maximum Likelihood Solution." Psychometrika , XX (1955), 193-200.