Straumal, B., Baretzky, B., Mazilkin, A., Protasova, S., Myatiev, A., & Straumal, P. (2009). Increase of Mn solubility with decreasing grain size in ZnO. Journal of the European Ceramic Society, 29(10), 1963-1970. doi:10.1016/j.jeurceramsoc.2009.01.005.