  We show that a specific skew-symmetric form of nonlinear hyperbolic problems
leads to energy and entropy bounds. Next, we exemplify by considering the
compressible Euler equations in primitive variables, transform them to
skew-symmetric form and show how to obtain energy and entropy estimates.
Finally we show that the skew-symmetric formulation lead to energy and entropy
stable discrete approximations if the scheme is formulated on
summation-by-parts form.
