References
- Ebbinghaus , H. 1885 . Memory: A contribution to experimental psychology . Translated by H.A. Ruger and C.E. Bussenius (1913). Originally published in New York by Teachers College, Columbia University. http://psy.ed.asu.edu/~classics/Ebbinghaus/index.htm
- Fisher , R.A. 1935 . The design of experiments , Edinburgh : Oliver and Boyd .