International Agency for Research on Cancer (IARC). (1983). "Coal Tar and Some Derivatives". IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 34.
National Institute for Occupational Safety and Health (NIOSH). (2016). Occupational Exposure to Coal Tar.
3.PubMed.gov: "Polycyclic Aromatic Hydrocarbons in Coal Tar and Cancer Risk", Environmental Health Perspectives, 2010.