1. Binzel, R. P. and Hubbard, W. B.: 1997, in S. A. Stern and D. J. Tholen (eds.), Pluto and Charon, University of Arizona Press: Tucson, pp. 85–102.
2. Boehnhardt, H. et al.: 2003, this volume.
3. Buie, M. et al.: 2003, MPEC 2003-Q58.
4. Burns, J.: 2002, Science 297, 942–943.
5. Burns, J., Carruba, V., and Gladman, B.: 2002, MPEC 2002-L30.