Kilder

• Davies, Paul: Other Worlds. Space, Superspace and the Quantum Universe. Touchstone, 1980.
• Kaku, Michio: Hyperspace. A Scientific Odyssey through Parallel Universes, Time Warps, and the 10th Dimension. Anchor Books, 1995.
• Kaku, Michio: Parallel Worlds. A Journey through Creation, Higher Dimensions, and the Future of the Cosmos. Anchor Books, 2006.
• Wolf, Fred Alan: Parallel Universes. The Search for Other Worlds. Simon & Schuster, 1990.