Towards possible origin of binding in non-abelian gauge theories
  Estimate of average energy of the non-abelian dipole in the instanton medium is calculated. This energy for the dipole in colour singlet state escalates linearly with the separation increasing for the point-like sources unscreened. And its 'tension' coefficient develops the magnitude pretty similar to one as inferred from the lattice QCD and other model approaches. 
S.V. Molodtsov, G.M. Zinovjev