IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 101 (2015): "Some Traditional Herbal Medicines, Some Mycotoxins, Naphthalene and Styrene."
FDA (2016). "Pyrrolizidine Alkaloids in Food—Analytical Methods and Risk Assessment."
World Health Organization (WHO). "Pyrollizidine alkaloids: Human health risks and prevention."
PubMed (PMID: 27755220): "Pyrrolizidine alkaloids: Mechanisms of toxicity, carcinogenicity and detoxification."