S. Syukrianto, U. Umarudin, K. Madurani, and F. Kurniawan, “Porcine Detection on Anti-Covid 19 Immunity Gelatin Capsules Sold at Market X in North Surabaya Using Quartz Crystal Microbalance (QCM) Sensors”, ijcs, vol. 10, no. 3, pp. 215-222, Nov. 2021.