V. V. Ponevchinskii, A. I. Goncharuk, V. I. Vasil'ev, N. I. Lebovka, M. S. Soskin, “Cluster self-organization of nanotubes in a nematic phase: The percolation behavior and appearance of optical singularities”, Pis'ma v Zh. Èksper. Teoret. Fiz., 91:5 (2010), 259–262; JETP Letters, 91:5 (2010), 241–244
