Covolume methods constitute a generalization to unstructured meshes of clas
sical staggered mesh techniques. In this paper, a fourth-order method is pr
oposed and it is proved rigorously that the order is indeed 4 in a standard
norm. This result is for structured meshes only, and for div-curl equation
s in two-dimensional space. Copyright (C) 1999 John Wiley & Sons, Ltd.