1. (1992). Disorders of vocal signalling in children. In , & (Eds.), Nonverbal vocal communication: Comparative and developmental approaches (pp. 192–204). Cambridge, U.K.: Cambridge University Press.
2. (1982). Intuition. How we think and act. New York: Wiley & Sons.
3. (1969). Attachment and loss: Vol. 1, Attachment. New York: Basic.
4. (1871). The descent of man. London: John Murray.
5. (1983). Infant cognition. In & (Eds.), Infancy and developmental psychobiology (pp. 689–782). Vol. 2 of (Gen. Ed.), Handbook of child psychology. New York: John Wiley & Sons.