(1983). Hidden meanings: The role of covert conceptual structures in children's development of language. In D. Rogers, & J. A. Sloboda (Eds.), The acquisition of symbolic skills (pp. 445-470). New York: Plenum Press.
Levelt, W. J. M., & Plomp, K.
(1968). The appreciation of musical intervals. In J. M. M. Aler (Ed.), Proceedings of the fifth International Congress of Aesthetics, Amsterdam 1964 (pp. 901-904). The Hague: Mouton.