APA Style Citation

Carl Sagan Quotes. (n.d.). BrainyQuote.com. Retrieved September 17, 2019, from BrainyQuote.com Web site: https://www.brainyquote.com/authors/carl-sagan-quotes_2

Chicago Style Citation

Carl Sagan Quotes. BrainyQuote.com, BrainyMedia Inc, 2019. https://www.brainyquote.com/authors/carl-sagan-quotes_2, accessed September 17, 2019.

MLA Style Citation

"Carl Sagan Quotes." BrainyQuote.com. BrainyMedia Inc, 2019. 17 September 2019. https://www.brainyquote.com/authors/carl-sagan-quotes_2