1. C. Zannoni, The Molecular Physics of Liquid Crystals, chapter 3” Distribution functions and order parameters”, 51–83. Academic Press, New York (1979).
2. C. Zannoni, Nuclear Magnetic Resonance of Liquid Crystals, chapter 1” Quantitative description of orientational order: Rigid molecules”, 1–34. Springer Netherlands (1985).
3. G. R. Luckhurst, Physical Properties of Liquid Crystals: Nematics, chapter 2.1” Orientational order: distribution functions and order parameters”, 57–88. INSPEC, The Institution of Electrical Engineers, London (2001).
4. G. R. Luckhurst, Biaxial Nematic Liquid Crystals: Theory, Simulation and Experiment, chapter 2” Biaxial Nematics: Order Parameters and Distribution Functions”, 25–53. John Wiley & Sons (2015).
5. Determination of the symmetry classes of orientational ordering tensors