BIRCH     H. G. Birch
The relation of previous experience to insightful problem solving.
Journal of Comparative Psychology, 1945, 38, 367-383

FLEMING     J. D. Fleming
Field Report: The state of the apes
Psychology Today, 1974, 7(8), 31-46

GARDNER & GARDNER     R. A. Gardner & B.T. Gardner
Teaching sign language to a chimpanzee
Science, 1969, 165, 664-672

HARLOW     Harry F. Harlow
The formation of learning sets.
Psychological Review, 1949, 56, 51-65

HAYES     C. Hayes
The Ape in Our House
New York: Harper, 1951

HOCKETT     Charles F. Hockett
Animal "languages" and human language.
Human Biology, 1959, 31, 32-39

KELLOGG & KELLOGG     W.N. Kellogg & L.A. Kellogg
The Ape and the Child
New York: McGraw-Hill, 1933

LINDEN     Eugene Linden
Apes, Men and Language
New York: Penguin, 1974

PREMACK     David Premack
Language in the chimpanzee?
Science, 1971, 172, 808-822.

SAGAN     Carl Sagan
The Dragons of Eden: Speculations on the Evolution of Human Intelligence
New York: Ballantine, 1977

VYGOTSKY     Lev Semenovich Vygotsky
Thought and Language
Cambridge, Massachusetts: MIT Press, 1962