Stability of multiquarks in an improved flip-flop model of confinement
  We review some recent studies on the string model of confinement inspired by the strong-coupling regime of QCD and its application to exotic multiquark configurations. This includes two quarks and two antiquarks, four quarks and one antiquark, six quarks, and three quarks and three antiquarks with a careful treatment of the corresponding few-body problem. 
J. Vijande, A. Valcarce, J.-M. Richard
hep-ph