New N=4 Superfields and Sigma-models
  In this note, we construct new representations of D=2, N=4 supersymmetry which do not involve chiral or twisted chiral multiplets. These multiplets may make it possible to circumvent no-go theorems about N=4 superspace formulations of WZWN-models. 
I.T. Ivanov, U. Lindstrom and M. Rocek