1. A new series of metric test-letters and words for determining the amount and range of accommodation;Oliver;Trans. Amer. Ophth. Soc.,1886
2. A stigmometric card test for illiterates;Fridenberg;Arch. of Ophth.,1910
3. Echelle optométrique universelle;Dor;Rev. gen. d'Opht.,1920
4. Test objects for the illiterate;Ewing;Amer. Jour. Ophth.,1920
5. Ueber die Verwendung photographisch verkleinerten Optotypen zur Bestimmung der Sehschärfe in der Nähe;Bjerke;Arch. f. Ophth.,1902