1. R. J. Glauber:Phys. Rev.,130, 2529 (1963).
2. Y. Kano:Ann. of Phys.,30, 127 (1964); see alsoL. Mandel:Phys. Lett.,10, 166 (1964).
3. See for exampleD. Middleton:An Introduction to Statistical Commutation Theory (New York, 1960), p. 36.
4. Strictly speaking, one should define the concept of homogeneity (and also that of isotropy) in terms of the invariance property of the average of an arbitrary function of field variables. However, in this paper we are only interested in the consequences of the invariance properties of the correlation tensors.
5. See for exampleK. Gottfried:Quantum Mechanics, vol.1:Fundamentals (New York, 1966), p. 409.