Han, W., Redlich, P., Seeger, T., Ernst, F., Rühle, M., Hsu, W., Chang, B., Grobert, N., Terrones, M., Zhu, Y., Kroto, H., & Walton, D.(2000).Aligned CNx Nanotubes Produced by the Pyrolysis of Ferrocene/C60 Mixtures in Ammonia Atmosphere.Applied Physics Letters,77, 1807–1809.