dx.doi.org/10.1103/physrevlett.90.100403
Phys. Rev. Lett.

Bretin, V, Rosenbusch, P, Shlyapnikov, G. V, & Dalibard, J. (2003). Quadrupole oscillation of a single-vortex Bose-Einstein condensate: evidence for Kelvin Modes. Phys.Rev.Lett., 90(Article number: 100403), 1–4. doi:10.1103/physrevlett.90.100403