N.B. Ivanova, N.V. Kazak, Yu.V. Knyazev, D.A. Velikanov, A.D. Vasiliev, L.N. Bezmaternykh, and M.S. Platunov, Structure and magnetism of copper substituted cobalt ludwigite Co₃O₂BO₃, Low Temp. Phys. 39, (2013) [Fiz. Nizk. Temp. 39, 913-918, (2013)] DOI: https://doi.org/10.1063/1.4818633.