References
- Duke-Elder, W. Stewart: Text-Book of Ophthalmology. Vol. I. The Development, Form, and Function of the Visual Apparatus, St. Louis. C. V. Mosby, 1933, p. 607.
- Lancaster, Walter B.: Refraction and Motility, Springfield, Ill., Charles C Thomas, 1952, pp. 226–232.
- Parks, Marshall M.: Lectures in Ocular Motility (W. B. Lancaster course, 1963), pp. 38, 39.