1. L. D. Landau and E. M. Lifshitz, Course of Theoretical Physics, Vol. 2: The Classical Theory of Fields (Nauka, Moscow, 1988; Pergamon, New York, 1971).
2. C. W. Misner, K. S. Thorne, and J. A. Wheeler, Gravitation (W. H. Freeman, San Francisco, 1973).
3. V. Mukhanov, Physical Foundations of Cosmology (Cambridge Univ. Press, New York, 2005).
4. M. Maggiore, Gravitational Waves (Oxford Univ. Press, Oxford, 2008).
5. S. Weinberg, Cosmology (Oxford Univ, Press, Oxford, 2008).