References
- Knapp, Phillip: Diagnosis and Surgical Treatment of Hypertropia, Am Orthop J, 21:29–37, 1971
- Knapp, Phillip: Symposium: The S.O. Classification and Treatment of S.O. Palsy, Am Orthoptic J, 24:18–22, 1974
- Knapp, Phillip and Moore, Sally: Diagnosis and Surgical Options in S.O. Surgery, Strabismus Surgery, Int. Ophthal. Clinic, (editors Helveston and Ellis), No. 16, 1976, p. 137.
- Knapp, Phillip: Parentic Squints, Symposium on Strabismus, Trans of the New Orleans Acad. of Ophthal., St. Louis, C.V. Mosby Co., 1978, pp. 353–355.
- Helveston, EM, Bick, S., and Ellis, FD: Differential Intraocular Pressure as an Indirect Measure of Generated Muscle Force. Ophthal Surg, Vol. 11, No. 6, June 1980.
- Helveston, EM: Superior Oblique Tuck for Superior Oblique Palsy, Australian Journal of Ophthalmology, (Submitted for publication).