S.  Wolf, Grioli, G., Eiberger, O., Friedl, W., Grebenstein, M., Hoppner, H., Burdet, E., Caldwell, D. G., Carloni, R., Catalano, M. G., Lefeber, D., Stramigioli, S., Tsagarakis, N. G., Damme, V. M., Ham, V. R., Vanderborght, B., Visser, L. C., Bicchi, A., and Albu-Schaeffer, A., ?Variable Stiffness Actuators: Review on Design and Components?,  IEEE/ASME Transactions on Mechatronics , vol. 21, no. 5, pp. 2418 - 2430, 2016 [Online]. Available: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7330025

G.  Grioli, Wolf, S., Garabini, M., Catalano, M. G., Burdet, E., Caldwell, D. G., Carloni, R., Friedl, W., Grebenstein, M., Laffranchi, M., Lefeber, D., Stramigioli, S., Tsagarakis, N. G., Damme, V. M., Vanderborght, B., Albu-Schaeffer, A., and Bicchi, A., ?Variable Stiffness Actuators: the user?s point of view?, Int. J. Robotics Research, vol. 34, no. 6, pp. 727-743, 2015 [Online]. Available: http://ijr.sagepub.com/cgi/reprint/0278364914566515v1.pdf?ijkey=anmgudvoLz7ZloP&keytype=finite

B.  Vanderborght, Albu-Schaeffer, A., Bicchi, A., Burdet, E., Caldwell, D. G., Carloni, R., Catalano, M. G., Eiberger, O., Friedl, W., Ganesh, G., Garabini, M., Grebenstein, M., Grioli, G., Haddadin, S., Hoppner, H., Jafari, A., Laffranchi, M., Lefeber, D., Petit, F., Stramigioli, S., Tsagarakis, N. G., Damme, V. M., Ham, V. R., Visser, L. C., and Wolf, S., ?Variable Impedance Actuators: a Review?, Robotics and Autonomous Systems, vol. 61, no. 12, pp. 1601?1614, 2013 [Online]. Available: http://www.sciencedirect.com/science/article/pii/S0921889013001188

B.  Vanderborght, Albu-Schaeffer, A., Bicchi, A., Burdet, E., Caldwell, D. G., Carloni, R., Catalano, M. G., Ganesh, G., Garabini, M., Grioli, G., Haddadin, S., Jafari, A., Laffranchi, M., Lefeber, D., Petit, F., Stramigioli, S., Tsagarakis, N. G., Damme, V. M., Ham, V. R., Visser, L. C., and Wolf, S., ?Variable Impedance Actuators: Moving the Robots of Tomorrow?, International Conference of Intelligent Robots and Systems - IROS 2012- Best Jubilee Video Award. 2012. 

R.  Gassert, Vanello, N., Chapuis, D., Hartwig, V., Scilingo, E. P., Bicchi, A., Landini, L., Burdet, E., and Bleuler, H., ?Active Mechatronic Interface for Haptic Perception Studies with Functional Magnetic Resonance Imaging: Compatibility and Design Criteria?, in Proc. IEEE Int. Conf. on Robotics and Automation, 2006, pp. 3832-3837.