6Wiberg G:RoentgenogrmOnic and anatomic studies on the patellofemaral joim:With special refercence Io chondmmalacia patella. Acta orthop Scand 12:319,1941.
7Baumgartl F: Das Kniegelenk.Berlin,Spinger-Verlag, 1944.
8Gasco J, Del Pino JM,Gomar-Sancko F : Double Patella : A case of duplication of the coronal plane. J Bone Joint Surg Br 69:602,1987.
9Insall J, Salvati E : patellar position in the normal knee joint[J]. Radiology, 1971,104:1012104.
10Fulkerson JP, Gossling HR : Anatomy of the knee joint lateral retinaculum.Clin Orthop 153:183,1980.