Electron structure, Zitterbewegung, and the new non-linear Dirac-like   equation
  The recent literature shows a renewed interest, with various independent approaches, in the classical theories for spin. Considering the possible interest of those results, at least for the electron case, we purpose in this paper to explore their physical and mathematical meaning, by the natural and powerful language of Clifford algebras (which, incidentally, will allow us to unify those different approaches). In such theories, the ordinary electron is in general associated to the mean motion of a point-like "constituent" Q, whose trajectory is a cylindrical helix. We find, in particular, that the object Q obeys a new, non-linear Dirac-like equation, such that --when averaging over an internal cycle (which corresponds to linearization)-- it transforms into the ordinary Dirac equation (valid for the electron as a whole). 
M. Pavsic, Erasmo Recami and W.A. Rodrigues Jr