1. Adams, M. A., Schultz, P. H., Sugita, S., and Goguen, J. D.: 1997, Lunar Planet. Sci. XXVIII, Abstract, p. 3.
2. A’Hearn, M., Belton, M. J. S., Delamere, A., and Blume, W. H.: 2005, Space Science Reviews (this volume).
3. Anderson, J. L. B., Schultz, P. H., and Heineck, J. T.: 2003, J. Geophys. Res. 108, E8, doi:10.1029/2003JE002075.
4. Anderson, J. L. B., Schultz, P. H., and Heineck, J. T.: 2004, Meteor. Planet. Sci. 39, 303.
5. Artem’eva, N. A., Kosarev, I. B. V., Nemchinov, I., Trubetskaya, I. A., and Shuvalov, V. V.: 2000, Solar System Res. 34, 453.