“SILICA SUPPORTED PERCHLORIC ACID (HCLO4-SIO2) AS ECOFRIENDLY REUSABLE CATALYSTS FOR GREEN SYNTHESIS OF TETRAHYDROBENZO[B]PYRAN DERIVATIVES BY GRINDING METHOD”, IJFANS, vol. 11, no. 12, pp. 3348–3353, Jan. 2022, Accessed: Aug. 24, 2026. [Online]. Available: http://www.ijfans.org/index.php/Journal/article/view/13213