Structural, compositional, and optical characterization of thin TiOxNy coatings fabricated by dual ion beam sputtering, Rizzo, Antonella, Mirenghi L., Tapfer Leander, Alvisi Marco, Vasanelli L., Sarto F., and Scaglione Salvatore , Proceedings of SPIE - The International Society for Optical Engineering, Volume 2776, Glasgow, UK, p.392-399, (1996)