Penrose, R. (2004). The road to reality: A complete guide to the laws of the universe (First American edition.). A.A. Knopf.
Chicago-viite (17. p.)Penrose, Roger. The Road to Reality: A Complete Guide to the Laws of the Universe. First American edition. New York: A.A. Knopf, 2004.
MLA-viite (8. p.)Penrose, Roger. The Road to Reality: A Complete Guide to the Laws of the Universe. First American edition. A.A. Knopf, 2004.
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