Walter Bagehot (1873). “Physics and Politics: Or, Thoughts on the Application of the Principles of "natural Selection" and "inheritance" to Political Society”, p.65
Benjamin Franklin, William-Temple Franklin (1818). “Memoirs of the Life and Writings of (the Same), Continued to the Time of His Death by William Temple Franklin. - London, H. Colburn 1818”, p.253
Jules Verne (2013). “Jules Verne Selected Works: 20 000 Leagues Under the Sea, Around the World in 80 Days, A Journey to the Centre of the Earth, From the Earth to the Moon, Five Weeks in a Balloon, The Mysterious Island”, p.634, Lulu Press, Inc