T-duality off shell in 3D Type II superspace
  We give the manifestly T-dual formulation of the massless sector of the classical 3D Type II superstring in off-shell 3D N=2 superspace, including the action. It has a simple relation to the known superspace of 4D N=1 supergravity in 4D M-theory via 5D F-theory. The pre potential appears as part of the vielbein, without derivatives. 
Martin Pol\'a\v{c}ek, Warren Siegel
hep-th