1. Krogh, T.E., Davis, D.W., and Corfu, F., 1984, Precise U-Pb zircon and baddeleyite ages for the Sudbury structure, in Pye, E.G., Naldrett, A. J., and Giblin, P.E., Eds., The Geology and Ore Deposits of the Sudbury Structure: Ontario Geol. Surv. Spec. Vol. 1,431-445.