1. Falk, R., Falk, R., and Levin, J.: 1980, ?A potential for learning probability of young children?, Educational Studies in Mathematics 11, 181?204.
2. Feller, W.: 1968, An Introduction To Probability Theory and its Applications, John Wiley, New York.
3. Fischbein, E.: 1975, The Intuitive Sources of Probabilistic Thinking in Children, D. Reidel, Dordrecht.
4. Goldberg, E.: 1966, ?Probability judgements by pre-school children: task conditions and performance?, Child Development 37, 157?167.
5. Hart, K. M. (ed.): 1981, Children's Understanding of Mathematics, John Murray, London.