1. Comments on relations between Piaget's theory and S-R theory;Berlyne,1962
2. L'apprentissage dans une situation a structure opératoire concrète;Gréco,1959
3. Clinical and statistical prediction;Holt;J. abnorm. soc. Psychol.,1958
4. Intelligence and experience;Hunt,1961
5. La genèse des structures logiques élémentaires; classifications et sériations;Inhelder,1959