Vertex Operators for AdS3 with Ramond Background
  This review gives results on vertex operators for the Type IIB superstring in an AdS3 x S3 background with Ramond-Ramond flux, which were presented at Strings 2000. Constraint equations for these vertex operators are derived, and their components are shown to satisfy the supergravity linearized equations of motion for the six-dimensional (2,0) theory of a supergravity and tensor multiplet expanded around AdS3 x S3 spacetime. 
L. Dolan