Simpler Superstring Scattering
  We give a new, manifestly spacetime-supersymmetric method for calculating superstring scattering amplitudes, using the ghost pyramid, that is simpler than all other known methods. No pictures nor non-vertex insertions are required other than the usual b and c ghosts of the bosonic string. We evaluate some tree and loop amplitudes as examples. 
Kiyoung Lee, Warren Siegel