Holographic Ricci dark energy: interacting model and cosmological constraints Tian-Fu Fu, Jing-Fei Zhang, Jin-Qian Chen and Xin Zhang Eur. Phys. J. C, 72 3 (2012) 1932 Published online: 24 March 2012 DOI: 10.1140/epjc/s10052-012-1932-2