(EN) History of Drug Metabolism: Discoveries of the Major Pathways in the 19th Century[collegamento interrotto], A.CONTI and M. H. BICKEL, DRUG METABOLISM REVIEWS, 6(1), 1-50 (1977): "Only in 1829 did Liebig discover the compound he named hippuric acid because he had isolated it from equine urine, and, in contrast to benzoic acid, it contained nitrogen". Anche: Copia archiviata (PDF), su medvetande.dk. URL consultato il 17 luglio 2010 (archiviato dall'url originale il 17 dicembre 2014)..
web.archive.org
(EN) History of Drug Metabolism: Discoveries of the Major Pathways in the 19th Century[collegamento interrotto], A.CONTI and M. H. BICKEL, DRUG METABOLISM REVIEWS, 6(1), 1-50 (1977): "Only in 1829 did Liebig discover the compound he named hippuric acid because he had isolated it from equine urine, and, in contrast to benzoic acid, it contained nitrogen". Anche: Copia archiviata (PDF), su medvetande.dk. URL consultato il 17 luglio 2010 (archiviato dall'url originale il 17 dicembre 2014)..
