Stephen A. Chandler,a Peter Hanson, Alec B. Taylor, Paul H. Walton and Allan W. Timmsb. Sandmeyer reactions. Part 5.1 Estimation of the rates of 1,5-aryl/aryl radical translocation and cyclisation during Pschorr fluorenone synthesis with a comparative analysis of reaction energetics. J. Chem. Soc., Perkin Trans. 2. 2001: 214–228. doi:10.1039/b006184k.