N. Raidl, B. Sartory, P. Supancic, and R. Danzer (2018). Modern Methods for the Microscopic Characterization of ZnO Varistor Grain Boundaries. Practical Metallography: Vol. 55, No. 4, pp. 192-202. © Carl Hanser Verlag GmbH & Co. KG ISSN 0032-678X