1. Spondylolisthesis Observation on its development progression, and genesis;HITCHCOCK, H., H.,1940
2. Normal flexibility according to age groups;KENDAL, H., D.,1948
3. Movements of the lumbar spinal column;ALLBROK, D.;J. BJ. S,1957
4. Spondylolisthesisand tight hamstrin;PHALEN, G., S.,1961
5. The mechanical disturbances resulting from lumbar disc space narrowing;JONCK, L., M.,1961