Theoretical interpretation of luminosity and spectral properties of GRB   031203
  We show how an emission endowed with an instantaneous thermal spectrum in the co-moving frame of the expanding fireshell can reproduce the time-integrated GRB observed non-thermal spectrum. An explicit example in the case of GRB 031203 is presented. 
Carlo Luciano Bianco, Maria Grazia Bernardini, Pascal Chardonnet,   Federico Fraschetti, Remo Ruffini, She-Sheng Xue