1. https://www.brainyquote.com/authors/niels-bohr-quotes
2. Les Prophéties, translated by Edgar Leoni and published in Wikisource free online library
https://en.wikisource.org/wiki/Les_Propheties
3. The Leibniz‐Clarke Correspondence
4. A Philosophical Essay on Probabilities 1814;Laplace,1951
5. Hawking, Stephen in Stephen Hawking Quotes
https://www.quotetab.com/quotes/by-stephen-hawking