1. Ametropia vs. heterophoria, etc;Zentmayer;Jour. Amer. Med. Assoc.,1924
2. Convergence deficiency;Mann;Brit. Jour. Ophth.,1940
3. Theory of heterophoria;Bielschowsky;Amer. Jour. Ophth.,1938
4. Signs and symptoms of heterophorias;Bielschowsky;Amer. Jour. Ophth.,1938
5. The importance of fusion;Clausen;Arch. f. Augenh.,1931