J. Gray

Well-posed and ill-posed behaviour of the ${\it\mu}(I)$ -rheology for granular flow

D. Schaeffer, P. Bohorquez, T. Barker, 2015, Journal of Fluid Mechanics.

Loss of hyperbolicity and ill-posedness of the viscous-plastic sea ice rheology in uniaxial divergent flow

J. Gray, 1999 .