Steiner, S. A., Baumann, T., Bayer, B. C., Blume, R., Worsley, M., Moberly Chan, W. J., Shaw, E. L., Schlögl, R., Hart, A. J., Hofmann, S., & Wardle, B. L. (2009). Nanoscale Zirconia as a Nonmetallic Catalyst for Graphitization of Carbon and Growth of Single- and Multiwall Carbon Nanotubes. Journal of the American Chemical Society, 131(34), 12144–12154. https://doi.org/10.1021/ja902913r