Sum rules for the nonperturbative piece of correlators (specifically, the v
ector current correlator) are discussed. The sum rule subtracting the pertu
rbative part is of the superconvergent type. Thus it is dominated by the bo
und states and the low-energy production cross section. It leads to a deter
mination of the gluon condensate [alpha(s)G(2)]. We find [alpha(s)G(2)] sim
ilar or equal to 0.048 +/- 0.030 GeV4. (C) 1999 Elsevier Science B.V. All r
ights reserved.