Spontaneous rotating vortex rings in a parametrically driven polariton fluidJ. O. Hamp, A. K. Balin, F. M. Marchetti, D. Sanvitto and M. H. SzymańskaEPL, 110 5 (2015) 57006DOI: https://doi.org/10.1209/0295-5075/110/57006
