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;
Kührt, E., & Keller, H. U. (1996). On the importance of dust in cometary nuclei. Earth, Moon and Planets, 72, 79-89.