Piaget, J., & Cook, M. (1977). The origin of intelligence in the child (Second edition.). Penguin Books.
Lua i Stíl Chicago (17ú heag.)Piaget, Jean, agus Margaret Cook. The Origin of Intelligence in the Child. Second edition. Harmondsworth: Penguin Books, 1977.
Lua MLA (9ú heag.)Piaget, Jean, agus Margaret Cook. The Origin of Intelligence in the Child. Second edition. Penguin Books, 1977.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.