Internal Rotations and Stress Tensor Symmetry in Theories of Nematic   Liquids and Solids
  The paper analyses kinematics and dynamics of internal rotations with spin and their effects on the constitutive relations for uniaxial (nematic) liquids and for weakly elastic nematic solids. It is shown that neglecting the internal rotational inertia terms and effects of director gradient made the stress symmetric. This not only highly simplifies the theories but also allows calculating all the kinematic variables of internal rotations without any additional constants, other than those presented in the simplified theory with symmetric stress. 
A. I. Leonov (U. of Akron), V. S. Volkov (Russian Academy of Sciences,   Moscow)