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2. Concepts of Time in Physics: A Synopsis
3. G.J. Witrow. What is time? Thames and Hudson, London. 1972. p. 125.
4. B. Greene. The fabric of the cosmos. Space, time, and the texture of reality. Allen Lane, London. 2004.
5. L. Smolin. The trouble with physics. The rise of string theory, the fall of science and what comes next. Penguin, London. 2006.