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
John Galsworthy (2015). “The Forsyte Saga Complete Edition: The Forsyte Saga + A Modern Comedy + End of the Chapter + On Forsyte ‘Change (A Prequel to Forsyte Saga): Complete Nine Novels”, p.658, e-artnow