N. Kristina, E. Resigia, and N. . Herawati, “Ammonium Sulphate (ZA) and Organic Fertilizer to Improve Yield and Quality of Shallot Bulb (Allium ascalonicum L.) on Recovered Ultisols”, J. appl. agricultural sci. technol., vol. 7, no. 3, pp. 259-271, Aug. 2023.