A. N. S. Nasution, B. . Irawan, and I. H. Rambe, “Development of Ethnomathematical-Based Student Worksheets for Gordang Sambilan Musical Instruments on Cone Slice Material for Class XI SMA Primbana Medan”, J. of Maths Tech and Edu, vol. 1, no. 1, pp. 19-29, Dec. 2021.