One-loop effective action for non-local modified Gauss–Bonnet gravity in de Sitter space Guido Cognola, Emilio Elizalde, Shin’ichi Nojiri, Sergei D. Odintsov and Sergio Zerbini Eur. Phys. J. C, 64 3 (2009) 483-494 Published online: 26 September 2009 DOI: 10.1140/epjc/s10052-009-1154-4