1. Ein einfaches Exophthalmometer;Hertel;Arch f Ophth,1905
2. Introduction to orbital disease;Harvey,1992
3. Orbital diseases and neuro-ophthalmology;Glaser,1992
4. Exophthalmometry;Chalfin,1990
5. Normal exophthalmometric values in children;Nucci;Am J Ophthalmol,1989