  In this paper we consider the Grioli-Koiter-Mindlin-Toupin
indeterminatecouple stress model. The main aim is to show that the traction
boundary conditions were not yet completely deduced. As it turns out, and to
our own surprise, restricting the boundary condition framework from the strain
gradient models to the couple stress model does not reduce to Mindlin's set of
accepted boundary conditions. We present therefore, for the first time the
complete, consistent set of traction boundary conditions.
