T. V.  Kotbagi, Biradar, A. V., Umbarkar, S. B., and Dongare, M. K., ?Isolation, characterization, and identification of catalytically active species in the MoO3/SiO2 catalyst during solid acid catalyzed reactions?, Chemcatchem, vol. 5, no. 6, pp. 1531-1537, 2013.