Where is the 3rd subgroup of GRBs?
  It is shown that in the duration-hardness plane the GRBs of the third intermediate subgroup are well defined. Their durations are intermediate (i.e. roughly between 2 and 10 seconds), but their hardnesses are the lowest. They are even softer than the long bursts. 
I. Horvath, A. Meszaros, L.G. Balazs and Z. Bagoly