On Renormalons and Landau Poles in Gauge Field Theories
  It is shown that the commonly accepted relationship between the Landau singularity in the running coupling constant of QED or QCD and the renormalon singularities in the Borel sums of perturbation theory expansions is only a particular feature of the restriction of the perturbative $\beta$--function to the one loop level. 
S. Peris (UAB) and E. de Rafael (CPT)