Mahmoud, S.S., et al. “Sol-Gel Synthesis, Characterization and Catalytic Activity of Pd Supported on Silica and Siloxane-Modified Silica”. Asian Journal of Chemistry, vol. 12, no. 4, Mar. 2010, pp. 1047-56, https://asianpubs.org/index.php/ajchem/article/view/23128.