Justus von Liebig (1859). “Familiar Letters on Chemistry, in its relation to Physiology, Dietetics, Agriculture, Commerce and Political Economy: Edited by John Blyth”, p.58
Justus von Liebig (1855). “Principles of agricultural chemistry with special reference to the late researches made in England: By Justus von Liebig. (Ed. by William Gregory)”, p.31
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
Justus von Liebig (1859). “Familiar Letters on Chemistry, in its relation to Physiology, Dietetics, Agriculture, Commerce and Political Economy: Edited by John Blyth”, p.21
Justus von Liebig (1842). “Chemistry in its applications to agriculture and physiology: By Justus Liebig. Edited from the manuscript of the author by Lyon Playfair”, p.176