G. M. ZIARANI, M. RAHIMIFARD, F. NOURI, and A. BADIEI, “Green one-pot, four-component synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives using amino-functionalized nanoporous silica SBA-15 under solvent-free conditions”, J. Serb. Chem. Soc., vol. 80, no. 10, pp. 1265–1272, Nov. 2015.