BillettR. O.Provisions for Individual Differences, Marking, and Promo- tion. (Bulletin, 1932, No. 17, National Survey of Secondary Education. U. S. Department of the Interior, Office of Education.)
2.
CornellE. L.The Variability of Children of Different Ages and Its Rela- tion to School Classification and Grouping. (University of the State of New York Bulletin; Educational Research Studies, 1937, No. 1)
3.
EllisR. S.The Psychology of Individual Differences. (D. Appleton-Century Co.: New York, 1930. 533 pp.)
4.
FreemanP. S.Individual Differences: The Nature and Causes of Variations in Intelligence and Special Abilities. (Henry Holt and Co.: New York, 1934. 355 pp.)
5.
HullC. L.Aptitude Testing. (World Book Co.: Yonkers.1928. 535 pp.)
6.
Nature and Nurture: Their Influence upon Intelligence (Part I); Their Influence upon Achievement (Part II). (Twenty-Seventh Yearbook of this Society, 1928)
7.
PlantJ. S.Personality and the Cultural Pattern. (The Commonwealth Fund: New York, 1937, 432 pp.)
8.
StmondsP. M.Diagnosing Personality and Conduct. (D. Appleton-Century Co.: New York, 1931. 602 pp.)
9.
The Grouping of Pupils. (The Thirty-Fifth Yearbook, Part I, of this Society, 1936)
