Drechsler, S.-L., Richter, J., Kuzian, R., Málek, J., Tristan, N., Büchner, B., et al. (2007). Helimagnetism and weak ferromagnetism in edge-shared chain cuprates. Journal of Magnetism and Magnetic Materials, 316, 306-312. doi:10.1016/j.jmmm.2007.03.200.