  Given a weight 2 and level p^2 modular form f, we construct two weight 3/2
modular forms (possibly zero) of level 4p^2 and non trivial character mapping
to f via the Shimura correspondence. Then we relate the coefficients of the
constructed forms to the central value of the L-series of certain imaginary
quadratic twists of f. Furthermore, we give a general framework for our
construction that applies to any order in definite quaternion algebras, with
which one can, in principle, construct weight 3/2 modular forms of any level,
provided one knows how to compute ideal classes representatives.
