1. Berliner Elektronenspeicherring - Gesellschaft für Synchrotronstrahlung m. b. H., Albert-Einstein-Str. 15, 12489 Berlin, Germany.
2. High Energy Accelerator Research Organization (KEK), Photon Factory (PF), Oho 1−1, Tsukuba, Ibaraki, 305–0801, Japan.
3. Determination of the Ellipticity of Light and of Optical Constants by Use of Two Reflection Polarizers