1. Loads on the spine during sitting;Andersson,1986
2. Lumbar disc pressure and myoelectric back muscle activity during sitting;Andersson;Scand J Rehab Med,1974
3. A category scale with ratio properties for intermodal and inter-individual comparisons;Borg,1980
4. Quasi-experimentation design and analysis issues for field settings;Cook,1979
5. Quasi-experimentation design and analysis issues for field settings;Cook,1979