1. Ueber Refraction und Achsenlaenge des menschlichen;Stroemberg;Auges. Acta Ophth.,1936
2. Visual acuity of young men;Sorsby;Brit. M.J.,1960
3. Ocular examination in school children;Sundmark;T. Social Med.,1964
4. Myopia in secondary schools of Sweden;Undgren;Nord. Med.,1953
5. Ueber die menschliche Refractioinskurve;Hess;Arch. f. Augenh.,1924