APA Style Citation

Stephen Hawking Quotes. (n.d.). BrainyQuote.com. Retrieved October 21, 2019, from BrainyQuote.com Web site: https://www.brainyquote.com/quotes/stephen_hawking_696270

Chicago Style Citation

Stephen Hawking Quotes. BrainyQuote.com, BrainyMedia Inc, 2019. https://www.brainyquote.com/quotes/stephen_hawking_696270, accessed October 21, 2019.

MLA Style Citation

"Stephen Hawking Quotes." BrainyQuote.com. BrainyMedia Inc, 2019. 21 October 2019. https://www.brainyquote.com/quotes/stephen_hawking_696270