C M Charles (1974) Teacher's petit Piaget (Belmont, Calif. : Fearon-Pitman)
Piaget, Jean and R. Garcia. (1974) Understanding Causality.
박양덕 (2000) A comparison of teachers' recognition of the early childhood mathematics education with parents'
안애리 (1993) Degree of Cognition about written numerals used everyday environment
Kamii C. (1985) Young Children Reinvent Arithmetic: Implications of Piaget's Theory.
Lauren B Resnick, Susan F Omanson (1987) Learning to understand arithmetic.