Förster, T., Garcia, F. A., Gruner, T., Kaul, E. E., Schmidt, B., Geibel, C., et al. (2013). Spin fluctuations with two-dimensional XY behavior in a frustrated S=1/2 square-lattice ferromagnet. Physical Review B, 87(18): 180401, pp. 1-5. doi:10.1103/PhysRevB.87.180401.