1. An extraordinary opportunity;Kahn;Am. J. Ophthalmol,1973
2. Lichter, P.R., Shaffer, R.N., and Martonyi, C.L.: Validity of Optic Disk Evaluation Using Steroid and Polaroid Photography. Prize-winning Exhibit at 1973 meeting of American Academy of Ophthalmology and Otolaryngology, Dallas, Texas, Sept. 1973.
3. An Introduction to Scientific Research;Wilson,1952