  We develop arguments on convexity and minimization of energy functionals on
Orlicz-Sobolev spaces to investigate existence of solution to the equation
$\displaystyle -\mbox{div} (\phi(|\nabla u|) \nabla u) = f(x,u) + h \mbox{in}
\Omega$ under Dirichlet boundary conditions, where $\Omega \subset {\bf R}^{N}$
is a bounded smooth domain, $\phi : (0,\infty)\longrightarrow (0,\infty)$ is a
suitable continuous function and $f: \Omega \times {\bf R} \to {\bf R}$
satisfies the Carath\'eodory conditions, while $h$ is a measure.
