Latif, N., and J. Pečarić. “Positive Semi-Definite Matrices, Exponential Convexity for Multiplicative Majorization and Related Means of Cauchy’s Type”. Rev. Anal. Numér. Théor. Approx., vol. 39, no. 1, Feb. 2010, pp. 50-68, doi:10.33993/jnaat391-919.