Kappa-Symmetry and Bogomol'ny Bound
  The paper analyzes the problem fixing the local fermionic gauge symmetry in the Green-Schwarz superstring theory,related to the covariant quantization of this theory.The gauge-fixing procedure reveals the connection between GS and NSR formalisms, conjectured earlier. The analysis relates the kappa-invariance to the Bogomol'ny-type condition,well-known in connection with D-brane theories. The BPS saturation condition appears to be a target space superpartner of the kappa-invariance condition. Relation to RR charges of p-brane solutions of the ten-dimensional supergravity is discussed. 
Dimitri Polyakov