M.  Sasidharan, Kiyozumi, Y., Mal, N. K., Paul, M., Rajamohanan, P. R., and Bhaumik, A., ?Incorporation of tin in different types of pores in SBA-15: synthesis, characterization and catalytic activity?, Microporous and Mesoporous Materials, vol. 126, no. 3, pp. 234-244, 2009.