Magnetic resonant mode in the low-energy spin-excitation spectrum of superconducting Rb2Fe4Se5 single crystals - J.T. Park; G. Friemel; Yuan Li; J.-H. Kim; V. Tsurkan; J. Deisenhofer; H.-A. Krug Von Nidda; A. Loidl; A. Ivanov; B. Keimer; D.S. Inosov (Physical Review Letters, 2011)