Update on four-family neutrino oscillations at Neutrino Factory
  The prospects of measuring the leptonic angles and CP-odd phases at a {\em neutrino factory} are discussed in the scenario of three active plus one sterile neutrino, motivated by the $\nu_\mu \raw \nu_e$ LSND signal. Sensitivity to the MNS mixing matrix angles at $O (10^{-3})$ is achieved with a 1 T detector at $\sim 1$ km from the source, whereas leptonic CP-violation can be measured through tau detection with a 1 kT detector at $\sim 100$ km. 
A. Donini, M.B. Gavela, P. Hernandez and S. Rigolin