1. 1) M. Yokota, F. Sugaya, H. Mifune, Y. Kobori, K. Shimizu, K. Nakai, S. Miyahara and Y. Shimizu: J. Japan Inst. Metals 66 (2002) 708–714.
2. 2) Ed. by T. Ooki, T. Oosawa, M. Tanaka and H. Chihara: The Comprehensive Dictionary of Chemistry, (Tokyo Kagakudouzin, Tokyo, 1989) p. 1563.
3. 3) Wan Chiapao: Sciences of Conservation & Archaeology 1(2) (1989) 32–36.
4. 4) M. Yokota, F. Sugaya, X. Q. Hang and T. K. He: J. Japan Inst. Metals 65 (2001) 893–895.
5. 5) Data compiled and evaluated by C. D. Wagner, A. V. Naumkin, A. K. Vass, J. W. Allison, C. J. Powell and J. R. Rumble Jr.: NIST X-Ray Photoelectron Spectroscopy Database, (NIST Standard Reference Database 20, V3.2 (Web Ver.), 2000).