K. M. Wibowo, A. Latif, F. Susanto, F. Fatiatun, and N. Che Ani, “Development and Acoustic Analysis of a Speaker-Output Stethoscope for Low-Cost Clinical Applications”, ijeeemi, vol. 7, no. 4, pp. 630–640, Oct. 2025, doi: 10.35882/ijeeemi.v7i4.125.