1. Normal and abnormal function of the foot;Root,1977
2. Motion of the first metatarsophalangeal joint;Hetherington;J. Foot Surg.,1989
3. Osteology, ch. 2;Sarrafian,1993
4. Structural alteration;Kelikian,1965
5. KLL progressive staging classification of hallux limitus and hallux rigidus;Kravitz;Lower Extremity,1994