String Corrections To The Riemann Curvature Tensor
  The string corrections to the Riemann Curvature tensor are found to first order in the string slope parameter, here proportional to $\g$. This is done for D=10 supergravity, the presumed low energy limit of string theory. We follow the perturbative approach. We also simplify a crucial result in our previous solution. 
S. Bellucci, D. O'Reilly
hep-th