A note on color neutrality in NJL-type models
  By referring to the underlying physics behind the color charge neutrality condition in quark matter, we discuss how this condition should be properly imposed in NJL-type models in a phenomenologically meaningful way. In particular, we show that the standard assumption regarding the use of two color chemical potentials, chosen in a very special way, is not justified in general. When used uncritically, such an approach leads to wrong or unphysical conclusions. 
Michael Buballa and Igor A. Shovkovy