[31] C.L. Vaughan: The Moter Power of Complexity. (Harvard Psychological Studies, vol. 2, 1906, p. 527.)
[32] G.M. Stratton: Some Experiments in the Perception of the Movement, Color, and Direction of Lights. (Psychological Review Monographs, vol. 10, 1908.)
[33] The experiments are being conducted and will be published by Miss L.M. Seeley.
[34] H. Münsterberg: Beiträge sur experimentellen Psychologie. (Book iv, 1892.)
[35] R.S. Woodworth: Accuracy of Voluntary Movement. (Psychological Review Monographs, vol. 8, 1899.)
[36] B.A. Lenfest: The Accuracy of Linear Movement. (Harvard Psychological Studies, vol. 2, 1906.)
[37] Ranschburg: Ueber die Bedeutung der Ähnlichkeit beim Erlernen, Behalten und bei der Reproduktion. (Journal für Psychologie und Neurologie, vol. 6.) Ranschburg: Zeitschrift für Psychologie und Physiologie der Sinnesorgane. (Vol. 80, 1902.)
[38] H. Kleinknecht: The Interference of Optical Stimuli. (Harvard Psychological Studies, vol. 2, 1906.)
[39] The experiments are being conducted and will be published by Miss O.E. Martin.
[40] Henry P. Kendall: Unsystematized, Systematized, and Scientific Management. (In Addresses and Discussions at the Conference on Scientific Management held at Dartmouth College, 1912.)