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. (2006). Comet nuclei: Morphology and implied processes of surface modification. Planetary and Space Science, 54(8), 808-829. doi:10.1016/j.pss.2006.05.001.