1. L. Ciupitu, I. Simionescu. Static Balancing of Mechanical Systems used in Medical Engineering Field – Approximate Balancing. In: Romanian Journal of Technical Science (SISOM '05, Bucharest, Romania, May 19-20, 2005) pp.296-303.
2. P. Cowan, K. Dennison, R. H. Nathan, J. Skorecki. Floating arm supports: Preliminary trail and further development. Proceedings of the Fourth World Congress on the Theory of Machines and Mechanisms, Newcastle-Upon-Tyne, England, 1975, pp.815-820.
3. B. L. Davis, P. R. Cavanagh. Simulating reduced gravity: a review of biomechanical issues pertaining to human locomotion. In: Aviat. Space Environ. Med., 1993, 64, pp.557-566.
4. H. P. Greene. Load compensator for spring counter-weighting mechanism. United States Patent 5, 400, 721, (1995).
5. J. L. Herder. Energy-free Systems. Theory, conception, and design of statically balanced spring mechanisms. PhD Thesis, Technische Universiteit Delft, The Nederland, ISBN 90-370-0192-0, (2001).