On the harmonic superspace language adapted to the Gelfand-Dickey   algebra of differential operators
  Methods developed for the analysis of non-linear integrable models are used in the harmonic superspace (HS) framework. These methods, when applied to the HS, can lead to extract more information about the meaning of integrability in non-linear physical problems. Among the results obtained, we give the basic ingredients towards building in the HS language the analogue of the G.D. algebra of pseudo-differential operators. Some useful convention notations and algebraic structures are also introduced to make the use of the harmonic superspace techniques more accessible. 
M. Hssaini, M. Kessabi, B. Maroufi and M.B.Sedra