Counterposed phase velocity and energy-transport velocity vectors in a   dielectric-magnetic uniaxial medium
  When a plane wave is launched from a plane surface in a linear, homogenous, dielectric-magnetic, uniaxial medium, we show that its phase velocity and the energy-transport velocity vectors can be counterposed (i.e., lie on different sides of the surface normal) under certain circumstances. 
A. Lakhtakia, M.W. McCall