  We briefly comment on a paper by Rubano and Scudellaro [astro-ph/0103335]
where they found general exact solutions for two classes of exponential
potentials in a scalar field model for quintessence. In that paper the authors
were led to some interesting conclusions after a proper choice of the
integration constants. By using dimensionless variables we show that the
integration constants can be found explicitly without additional assumptions.
In consequence we revise some results and conclusions in that paper. We also
reproduce observations for Type-1a supernovae with good accuracy.
