1. Cormack, R. H. (1984). Stereoscopic depth perception at far viewing distances.Perception & Psychophysics,35, 423–428
2. Enright, J. T. (1984). Saccadic anomalies Vergence induces large departures from ball-and-socket behavior.Vision Research,24. 301–308
3. Graham, C. H. (1965). Visual space perception. In C. H. Graham (Ed.),Vision and visual perception. New York: Wiley.
4. Gulick, W. L. &Lawson, R. B. (1976).Human stereopsis- A psychophysical approach New York Oxford University Press
5. Helmholtz, H. Von (1962).Treatise on physiological optics (Vol. 3, J. P C. Southall, Trans.). New York: Dover. (Original work published 1910)