Keller, H. U. Department Planets and Comets, Max Planck Institute for Solar System Research, Max Planck Society; MPI for Aeronomy, Max Planck Institute for Solar System Research, Max Planck Society;
Basilevsky, A. T., & Keller, H. U. (2007). Craters, smooth terrains, flows, and layering on the comet nuclei. Solar System Research, 41(2), 109-117. doi:10.1134/S0038094607020037.