
 Mathematics of Computation 
  As a consequence, a posteriori error estimators based on those recovery methods are asymptotically exact. 
  R.E. Bank and J. Xu, Asymptotically exact a posteriori error estimators, Part I: Grid with superconvergence, preprint, to appear in SIAM J. Numer. 
  W. Hoffmann, A.H. Schatz, L.B. Wahlbin, and G. Wittum, Asymptotically exact a posteriori estimators for the pointwise gradient error on each element in irregular meshes I: A smooth problem and globally quasiuniform meshes, Math. 
 www.ams.org /mcom/200473247/S0025571803016004/home.html (661 words) 
