References
- Edelman PM: Orthoptics. A Syllabus of Ocular Motility. Amer Acad Ophth, 1987, p.viii.
- Duke-Elder S, Wybar K: Ocular Motility and Strabismus in System of Ophthalmology, Vol. 6, 1973, p.433.
- Berens C: A prism bar of thermoplastic material for measuring high degrees of squint. Trans Am Ophthalmol Soc 1939; 37: 404.
- Berens C: A test for binocular vision particularly applicable to the examination of amblyopic children (modified Worth test). Trans Am Ophthalmol Soc 1939; 37: 406–407.