CraikK. J. W.ZangwellO. L.Observations relating to the threshold of a small figure within the contour of a closed-line figure. Brit. J. Psychol., 1939, 30, 139–150.
2.
VernonM. D.Comment on “The enclosing contour effect.”Percept. Mot. Skills, 1961, 13, 334.