Justus von Liebig (1859). “Familiar Letters on Chemistry, in its relation to Physiology, Dietetics, Agriculture, Commerce and Political Economy: Edited by John Blyth”, p.5
Michel de Montaigne (1853). “The Works of Michael de Montaigne: Comprising His Essays, Letters, and Journey Through Germany and Italy. With Notes from All the Commentators, Biographical and Bibliographical Notices &c., &c”, p.271