McGill S: Low back disorders: Evidence-based prevention and rehabilitation, Human Kinetics, USA, 2002, pp118-124.
Oliver J: Back Care: An illustrated guide. Butterworth-Heinemann, Oxford, 1994, pp107-118.
Hagen KB, et al.: Ratings of perceived thigh and back exertion in forest workers during repetitive lifting using squat and stoop techniques, Spine 19: 2511-2517.1994.