“The Effect of Ultisols Subsoil Combined With Mexican Sunflower (Tithonia Diversifolia) Compost and Vermicompost on Pre-Nursery Growth of Oil Palm Seedling”. Akta Agrosia, vol. 26, no. 2, Dec. 2023, pp. 50-58, doi:10.31186/aa.26.2.50-58.