1. L. Gong, Y.Wang and X. Cheng: submitted to J. Porous Materr (2014).
2. R. Barea, M.Osendi and P .Miranzo: submitted to J .Am Ceram Soc-(2005).
3. T. Tomita, S. Kawasaki and K. Okada: submitted to J. Porous Mater (2004).
4. W. Yan and B. Han: submitted to Am Ceram Soc Bull (2005).
5. W. Yan: submitted to Am Ceram Soc Bull (2006).