P.  Dario, Bicchi, A., Vivaldi, F., and Pinotti, P. C., ?Tendon Actuated Exploratory Finger With Polymeric, Skin-like Tactile Sensor?, in Proc. IEEE Int. Conf. on Robotics and Automation, St. Louis, MO, USA., 1985. 

P.  Dario, Bardelli, R., De Rossi, D., Wang, L. R., and Pinotti, P. C., ?Touch-sensitive polymer skin uses piezoelectric properties to recognize orientation of objects?, SENSOR REVIEW, vol. 4, pp. 194?198, 1982.