Charles Mackay (1852). “Memoirs of extraordinary popular delusions and the madness of crowds: Illustrated with numerous engravings. (2 Thle in 1 vol.). I”, p.7
Adam Smith (1869). “Essays On, I. Moral Sentiments: II. Astronomical Inquiries; III. Formation of Languages; IV. History of Ancient Physics; V. Ancient Logic and Metaphysicis; VI. The Imitative Arts; VII. Music, Dancing, Poetry; VIII. The External Senses; IX. English and Italian Verses”, p.14