M. Yusuf, Y. Firdaus, M. R. Maulana, A. Hushori, and A. Sopiyan, “Analysis of the Obstacles Faced by Smallholding Farmers in Improving Rubber Production After COVID-19 in South Sumatra Province, Indonesia”, Futur Soc, vol. 3, no. 3, pp. 4–23, Aug. 2025.