Constant curvature f(R) gravity minimally coupled with Yang–Mills field S. Habib Mazharimousavi, M. Halilsoy and T. Tahamtan Eur. Phys. J. C, 72 3 (2012) 1958 Published online: 28 March 2012 DOI: 10.1140/epjc/s10052-012-1958-5