1. Pushkina, I., and Zukhar, V., Nauka i Zhizn, 4, 60 (1964).
2. Rybchinskiy, T., Soviet Union, 171, 16 (1964).
3. Svyadoshch, A. M., Voprosy psikhologii, 1 (1962).
4. Loomis, A. L., Harvey, E. N., and Hobart, G. A., J. Exp. Psychol., 19, 249 (1936).
5. Fox, B. H., and Robbin, J. S., J. Exp. Psychol., 43, 75 (1952).