1. Grolman B : A New Tonometer System, Am J Optom and Arch Am Acad Optom, 49: 8, 646-60, 1972.
2. Forbes M, Pico G, Grolman B : A Non-Contact Applanation Tonometer. Arch Ophthalmol. 1974, 91: 134–40.
3. Halber P, Previte L, Yellen M : ‘Report on Clinical Experience with NCT’. Proceedings of the International Glaucoma Symposium - Albi, Nov 1974.
4. Decker T and Keuther C : American Optical Non-Contacting Tonometer Evaluation. Presented to Am Acad of Optom. Annual Meeting in San Francisco, Dec 1973.
5. Draeger J, Jessen K, Haselmann G : Klinische und experimentelle Untersuchungen mit dem Non-Contact-Tonometer. Klin Mbl Augenheik. 1975, 167: 27–34.