Reflectance, fluorescence yield, and photoelectron spectroscopy of CaF2 in the 10 to 100 eV range R. T. Williams, D. J. Nagel and M. N. Kabler J. Phys. Colloques, 41 C6 (1980) C6-439-C6-442 DOI: 10.1051/jphyscol:19806114