1. Vergence and accommodation III: proposed definitions of the AC/A ratios;Alpern;American Journal of Ophthalmology,1959
2. Developmental aspects of the Brüchner test;Archer;Ophthalmology,1988
3. Accommodation, convergence and ageing;Breinin;Documenta Ophthalmologica,1973
4. Photographical calibration of the Hirschberg test;Brodie;Investigative Ophthalmology and Visual Science,1987