1. Appleton, L. E. 1910.A Comparative Study of the Play Activities of Adult Savages and Civilized Children; an Investigation of the Scientific Basis of Education, 34Chicago: Univ. Chicago Press.
2. Bernard, L. L. 1924.Instinct: a Study in Social Psychologv, 550New York: Holt.
3. Bett, H. 1924.Nursery Rhymes and Tales: Their Origin and History, 131London: Methuen.