Levine, Barry (2003 թ․ հունվարի 1). Principles of Forensic Toxicology (անգլերեն). Amer. Assoc. for Clinical Chemistry. էջեր 198–201. ISBN9781890883874. «Dihydrocodeine … [is a derivative] of codeine.... Heroin … is obtained synthetically … from morphine…. Hydrocodone is … derived from codeine…. Oxycodone is … derived from thebaine…. Oxymorphone is … derived from thebaine.»