Lebernegg, S., Schmitt, M., Tsirlin, A. A., Janson, O., & Rosner, H. (2013). Magnetism of CuX2 frustrated chains (X = F, Cl, Br): Role of covalency. Physical Review B, 87(15): 155111, pp. 1-11. doi:10.1103/PhysRevB.87.155111.