1. On the Anomalies of Accommodation and Refraction of the Eye;Donders,1864
2. Textbook of Ophthalmology. 5th ed;Duane,1917
3. A comparison of Duane's and Donders tables of the amplitude of accommodation;Hofstetter;Am J Optom Arch Am Acad Optom,1944
4. Useful age-amplitude formula;Hofstetter;Optom World,1950
5. How to prescribe spectacles for presbyopia;du Toit;Community Eye Health,2006