1. Gibson, E. J, Osser, H., Schiff, W., & Smith, J. An analysis of critical features of letters. tested by a confusion matrix. In Final Report, Cooperative Research Project No. 639 with the Office of Education,A basic research program on reading,
2. Neisser, U. Visual search.Scient. American, 1964, 210, 94–101.
3. Neisser, U., Novick, R., &Lazar, R. Searching for ten targets simultaneously.Percept. mot, Skills, 1963, 17, 955–961.