From methyl dinaphthyl ketone: Clar, Ber. 62, 350, 1378 (1929); Fieser, Dietz, ibid. 1827; Bachmann, J. Org. Chem. 1, 347 (1937). Separation by chromatography: Winterstein, Sch"on, Z. Physiol. Chem. 230, 146 (1934). Absorption spectrum: Mayneord, Roe, Proc. R. Soc. London A152, 299 (1935). Review: E. Clar, Polycyclic Hydrocarbons Vol. 1 & 2 (Academic Press, New York, 1964). Review of carcinogenic risk: IARC Monographs 3, 178-196 (1973); of toxicology and human exposure: Toxicological Profile for Polycyclic Aromatic Hydrocarbons (PB95-264370, 1995) 487 pp.