Horizon Geometry, Duality and Fixed scalars in Six Dimensions
  We consider the problem of extremizing the tension for BPS strings in D=6 supergravities with different number of supersymmetries. General formulae for fixed scalars and a discussion of degenerate directions is given. Quantized moduli, according to recent analysis, are supposed to be related to conformal field theories which are the boundary of three dimensional anti-de Sitter space time. 
L. Andrianopoli, R. D'Auria, S. Ferrara, M.A. Lledo