Mathematical Review: MR3178556 Harris, Isaac; Cakoni, Fioralba; Sun, Jiguang Transmission eigenvalues and non-destructive testing of anisotropic magnetic materials with voids. Inverse Problems 30 (2014), no. 3, 035016, 21 pp

The highlights of the article under review are: (a) the role of transmission eigenvalues in {Tikhonov} regularisation, (b) the existence of transmission eigenvalues and (c) the relation between inhomogeneities of a scatterer and transmission eigenvalues. Many publications and articles, including the one under review, do not address the following properties: (m1) any material medium exhibits parameters (the matrices A and N of the article), which depend on frequency; (m2) the real and imaginary parts of permittivities and permeabilities are subject to the {Kramers-Kronig} relations.