Synthesis and characterization from Raman spectroscopy of pristine, potassium-doped and rubidium-doped fullerenes C60/C70 A. Zahab, J.L. Sauvajol, L. Firlej, R. Aznar et P. Bernier J. Phys. I France, 2 1 (1992) 7-13 DOI: 10.1051/jp1:1992119