Ali, Muhammad. Goodreads. http://www.goodreads.com/quotes/tag/friendship.
Bacon, Francis. Brainy Quote. http://www.brainyquote.com/quotes/quotes/f/francisbac403060.html.
Buddha. Brainy Quote. http://www.brainyquote.com/quotes/keywords/mind.html.
Camus, Albert. Brainy Quote. http://www.brainyquote.com/quotes/quotes/a/
albertcamu100779.html#hapi65ZTGoOMOL4j.99.
Cicero, Marcus Tullius. Brainy Quote. http://www.brainyquote.com/quotes/quotes/m/marcustull130785.html.
Epicurus. Goodreads. http://www.goodreads.com/quotes/tag/friendship?page=28.
Evans, Jules. Quoted in Philosophy for Life: And Other Dangerous Situations. Goodreads. http://www.goodreads.com/work/quotes/19236762-philosophy-for-life-and-other-dangerous-situations.
Kaling, Mindy. Quoted in Is Everyone Hanging Out Without Me?. Goodreads. http://www.goodreads.com/
work/quotes/15237902-is-everyone-hanging-out-without-me-and-other-concerns?page=2.
Lewis, C.S. Quoted in The Four Loves. Goodreads. http://www.goodreads.com/work/quotes/
14816053-the-four-loves.
Marx, Groucho. Quoted in The Essential Groucho: Writings by, for, and about Groucho Marx. Goodreads. http://www.goodreads.com/quotes/search?utf8=✓&q=friends&commit=Search.
Nietzsche, Friedrich. Brainy Quote. http://www.brainyquote.com/quotes/quotes/f/friedrichn166254.html.
Nouwen, Henri J.M. Quoted in The Road to Daybreak: A Spiritual Journey. Goodreads.
http://www.goodreads.com/quotes/tag/friendship.
Plutarch. Brainy Quote. http://www.brainyquote.com/quotes/quotes/p/
plutarch105273.html#V6XGJfwJOlbZFSQv.99.
Rockefeller, John D. Jr. The Quotations Page. http://www.quotationspage.com/
search.php3?homesearch=friendship&page=6.
Rogers, Fred. Goodreads. http://www.goodreads.com/quotes/tag/friendship?+page=8&page=8.
Thoreau, Henry David. Brainy Quote. http://www.brainyquote.com/quotes/authors/h/henry_david_thoreau.html.
Young, Neil. Quoted in Waging Heavy Peace: A Hippie Dream. Goodreads. http://www.goodreads.com/
work/quotes/19174134-waging-heavy-peace-a-hippie-dream.