Nonminimal string corrections and supergravity

We reconsider the well-known issue of string corrections to supergravity theory. Our treatment is carried out to second order in the string slope parameter. We establish a procedure for solving the Bianchi identities in the nonminimal case, and we solve a long standing problem in the perturbative expansion of D = 10, N = 1 string corrected supergravity, obtaining the H sector tensors, torsions and curvatures.