APA Style Citation

Stephen Hawking Quotes. (n.d.). BrainyQuote.com. Retrieved October 19, 2019, from BrainyQuote.com Web site: https://www.brainyquote.com/quotes/stephen_hawking_447569

Chicago Style Citation

Stephen Hawking Quotes. BrainyQuote.com, BrainyMedia Inc, 2019. https://www.brainyquote.com/quotes/stephen_hawking_447569, accessed October 19, 2019.

MLA Style Citation

"Stephen Hawking Quotes." BrainyQuote.com. BrainyMedia Inc, 2019. 19 October 2019. https://www.brainyquote.com/quotes/stephen_hawking_447569