High-temperature ferromagnetism of Li-doped vanadium oxide nanotubesA. I. Popa, E. Vavilova, Y. C. Arango, V. Kataev, C. Täschner, H.-H. Klauss, H. Maeter, H. Luetkens, B. Büchner and R. KlingelerEPL, 88 5 (2009) 57002DOI: https://doi.org/10.1209/0295-5075/88/57002