  We consider cosmological models in scalar tensor theories of gravity that
describe an accelerating universe, and we study a family of inverse power law
potentials, for which exact solutions of the Einstein equations are known. We
also compare theoretical predictions of our models with observations. For this
we use the following data: the publicly available catalogs of type Ia
supernovae and high redshift Gamma Ray Bursts, the parameters of large scale
structure determined by the 2-degree Field Galaxy Redshift Survey (2dFGRS), and
measurements of cosmological distances based on the Sunyaev-Zel'dovich effect,
among others.
