Consistency of Super-Poincare Covariant Superstring Tree Amplitudes
  Using pure spinors, the superstring was recently quantized in a manifestly ten-dimensional super-Poincar\'e covariant manner and a covariant prescription was given for tree-level scattering amplitudes. In this paper, we prove that this prescription is cyclically symmetric and, for the scattering of an arbitrary number of massless bosons and up to four massless fermions, it agrees with the standard Ramond-Neveu-Schwarz prescription. 
Nathan Berkovits and Brenno Carlini Vallilo (IFT/UNESP, Sao Paulo)