Saturn's equinoctial auroras - Nichols,JD; Badman,SV; Bunce,EJ; Clarke,JT; Cowley,SWH; Crary,FJ; Dougherty,MK; Gerard,J-C; Grodent,D; Hansen,KC; Kurth,WS; Mitchell,DG; et al. (GEOPHYSICAL RESEARCH LETTERS, 2009)