Zhang, J., Shaw, A., Amoozgar, M., Friswell, M., & Woods, B. K. S. (2019). Bidirectional Spiral Pulley Negative Stiffness Mechanism for Passive Energy Balancing. Journal of Mechanisms and Robotics, 11(5), p. 054502. doi:10.1115/1.4043818

Zhang, Jiaying, Alexander Shaw, Mohammadreza Amoozgar, Michael Friswell, and Benjamin K. S. Woods. "Bidirectional Spiral Pulley Negative Stiffness Mechanism for Passive Energy Balancing." Journal of Mechanisms and Robotics 11, no. 5 (2019): 054502.

Zhang, Jiaying, et al. "Bidirectional Spiral Pulley Negative Stiffness Mechanism for Passive Energy Balancing." Journal of Mechanisms and Robotics 11.5 (2019): 054502.