1. J.G. Bednorz and K.A. Muller Z. Phys. B64: 189 (1986).
2. K. Mendelssohn, “The Quest for Absolute Zero; the Meaning of Low Temperature Physics”, Taylor and Francis, Ltd., London, (1977).
3. See, for example, I. Kolin, “The Evolution of the Heat Engine”, Longman Group Ltd., London (1972).
4. J.A. Cunningham and R.A. Mollicone, S.P.I.E., V. 253: 170 (1980).
5. W.A. Steyert; J. de Physique 39: C6–1598 (1978).