Radial and vertical epicyclic frequencies of Keplerian motion in the field of Kerr naked singularities - Comparison with the black hole case and possible instability of naked-singularity accretion discs
and
A&A, 437 3 (2005) 775-788
Published online: 30 June 2005
DOI: 10.1051/0004-6361:20052825