van der Roer N, van Tulder MW, Barendse JM, van Mechelen W, Franken WK, Ooms AC, de Vet HC. Cost-effectiveness of an intensive group training protocol compared to physiotherapy guideline care for sub-acute and chronic low back pain: design of a randomised controlled trial with an economic evaluation. [ISRCTN45641649]. BMC Musculoskelet Disord. 2004 Nov 23;5:45.
Biddle S, Gorely T, Stensel D. Health-enhancing physical activity and sedentary behaviour in children and adolescents . Journal of Sports Sciences 2004; 22: 679 - 701
Grenier SG, McGill SM. Quantification of lumbar stability by using 2 different abdominal activation strategies. Archives of Physical Medicine and Rehabilitation. 2007; 88: 54.