Nonlocal Gluon Condensate from the Dyson--Schwinger Equations
  We establish a novel method of obtaining the gauge-invariant bilocal condensate of gluon fields from the solutions of the Dyson--Schwinger equations (DSE) which works in the infrared and ultraviolet limits. We present explicit results for SU(3) case in four dimensions, and compare to other related analytical and lattice results. 
A. V. Zayakin and J. Rafelski