LELLI M ET AL: 'Fast characterization of functionalized silica materials by silicon-29 surface-enhanced NMR spectroscopy using dynamic nuclear polarization', JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 133, no. 7, 31 January 2011 (2011-01-31), USA, pages 2104 - 2107, XP002665059, DOI: 10.1021/JA110791D