C. Papenfuss, J. Verhas and W. Muschik
A simplified thermodynamic theory for biaxial nematics
Z. Naturforsch. 50a, 1995, 795-804

A continuum theory of a biaxial nematic phase in liquid crystals is presented. The liquid crystalline ordering is described by a field of three unit vectors. Because these are macroscopic directors, the present approach is a generalization of the Ericksen-Leslie theory to biaxial nematics. The applied tools from nonequilibrium thermodynamics are classical Linear Irreversible Thermodynamics and Gyarmati's variational principle.