1. F.J. Dyson and A. Lenard, J. Math. Phys. 8 (1967) 423; A. Lenard and F.J. Dyson, J. Math. Phys. 9 (1968) 698.
2. F.J. Dyson, in: Brandeis University Summer Institute in Theoretical physics (1966) eds. M. Chretien, E.P. Gross and S. Deser ( Gordon and Breach, New York 1968 ), Vol. 1, p. 179.
3. A. Lenard, in: Statistical mechanics and mathematical problems, ed. A. Lenard, Lecture Notes in Physics ( Springer, New York, 1973 ), Vol. 20, p. 114.
4. P. Federbush, J. Math. Phys. 16 (1975) 347, 706.
5. E.H. Lieb and W.E. Thirring, Phys. Rev. Lett. 35 (1975) 687.