Tang, Y. H., X. C. Li, J. L. Li, L. W. Lin, H. F. Xu, and B. Y. Huang. “Experimental Evidence for the Formation Mechanism of Metallic Catalyst-Free Carbon Nanotubes”. Nano-Micro Letters, vol. 2, no. 1, Feb. 2010, pp. 18-21, doi:10.1007/BF03353611.