Instability of Black Holes with a Gauss–Bonnet Term Wha-Keun Ahn, Bogeun Gwak, Bum-Hoon Lee and Wonwoo Lee Eur. Phys. J. C, 75 8 (2015) 372 Published online: 15 August 2015 DOI: 10.1140/epjc/s10052-015-3568-5