Canonical Equivalence between Super D-string and Type IIB Superstring
  We show that the super D-string action is canonically equivalent to the type IIB superstring action with a world-sheet gauge field. Canonical transformation to the type IIB theory with dynamical tension is also constructed to establish the SL(2,Z) covariance beyond the semi-classical approximations. 
Yuji Igarashi, Katsumi Itoh, Kiyoshi Kamimura and Rie Kuriki