Emissivity measurements of opaque gray bodies up to 2000 °C by a dual-frequency pyrometer L. Biasetto, M. Manzolaro and A. Andrighetto Eur. Phys. J. A, 38 2 (2008) 167-171 Published online: 06 November 2008 DOI: 10.1140/epja/i2008-10666-6