Hemmer,. J.L. Schwartz. At. 2008. Population vector code: a geometric universal as actuator Biol. Cybern. 98.509-518. Velliste. M. Pereki Spalding. MC_ Whitford. AS. Schwartz. A.B.2008. Cortical control of a prosthetic arm for self-feeding. Nature 453.1098-1101. Waldeit S. Preisst. It, Derma& E., Braun, C.