1. Landa, A. R., Gonzalez, M. and Hernandez, M. T., Carbon microstructure on grain boundaries of corundum. 3th Int. Conf. On Inorg. Materials, Konstanz, Germany, 2002.
2. ASTM standard designation C20-87.
3. Unpublished results.
4. Mollá, J. and Ibarra, A., A System for the Measurement of Dialectic Properties of Insulator Materials Report EUR-CIEMAT Vol. 89/13, 1989.
5. Precise measurement of dielectric properties at frequencies from 1 kHz to 100 MHz