Quotation:

 Ignacio Estrada quotes

 Socrates quotes (Ancient Greek Philosopher, 470 BC-399 BC)

 Ralph Waldo Emerson quotes (American Poet, Lecturer and Essayist, 1803-1882)

 Robert M. Hutchins quotes (American Educator and Writer, active in forming the Committee to Frame a World Constitution (1945), led the Commission on Freedom of the Press (1946), and vigorously defended academic freedom, opposing faculty loyalty oaths in the 1950s. 1899-1977)

 Phyllis Diller quotes (American comedienne and actress, born 1917)

 Henry Brooks Adams quotes (American writer, 1838-1918)

 Aristotle quotes (Ancient Greek Philosopher, Scientist and Physician, 384 BC-322 BC)

 John Steinbeck quotes (American Novelist and Writer, Nobel Prize for Literature for 1962, 1902-1968)

 Kahlil Gibran quotes (Lebanese born American philosophical Essayist, Novelist and Poet. 1883-1931)