1. For some recent reviews, see: (a) De Jeu WH (1992) In: Martelucci S, Chester AN (eds) Phase transitions in liquid crystals. Plenum Press, New York, chaps 1–3
2. Osipov MA (1998) In: Goodby J, Demus D (eds) Handbook of liquid crystals, 2nd edn, Wiley-VCH, Berlin
3. Maier W, Saupe A (1959) Z Naturforschg 14a: 882; Maier W, Saupe A (1960) 15a: 287
4. Pohl L, Eidenschink R, Krause J, Weber G (1978) Phys Lett A 65: 169
5. Demus D, Demus H, Zaschke H (1983) Flüssige Kristalle in Tabellen, 2nd edn. VEB Verlag, Leipzig