“Discovery of Five Quasars at z>4 Using the Second Palomar Sky Survey” J.D. Kennefick, R.R. de Carvalho, S.G. Djorgovski, M.M. Wilber, E.S. Dickson, N. Weir, U. Fayyad, and J. Roden. The Astronomical Journal Vol. 110, No. 1, pp. 78-86, July (1995).