Jorda, L. MPI for Aeronomy, Max Planck Institute for Solar System Research, Max Planck Society; Department Planets and Comets, Max Planck Institute for Solar System Research, Max Planck Society;
Licandro, J., Bellot-Rubiot, L. R., Böhnhardt, H., Casas, R., Goetz, B., Gomez, A., et al. (1998). The rotation period of C/1995 01 (Hale-Bopp). Astrophysical Journal, 501, L221-L225.