From Quark-Gluon Universe to Neutrino Decoupling: 200<T<2MeV
  The properties of the quark and hadron Universe are explored. Kinetic theory considerations are presented proving that hadron abundances after phase transformation from quarks to hadrons remain intact till abundances of hadrons become irrelevant. The hadronization process and the evolution of hadron yields is described in detail. 
Michael J. Fromerth, Inga Kuznetsova, Lance Labun, Jean Letessier, and   Jan Rafelski
nucl-th astro-ph.CO hep-ph