Lídia P. de S. Teixeira and Ian A. Simpson, “Total Nutrient Element Status of Subsistence Agriculture Soils in Angola”, ASRJETS-Journal, vol. 97, no. 1, pp. 232–261, May 2024, Accessed: Sep. 24, 2025. [Online]. Available: https://asrjetsjournal.org/American_Scientific_Journal/article/view/10206