M. Marwanto, N. Nasiroh, B. G. Mucitro, and M. Handajaningsih, “Effects of Combined Application of Cow Manure And Inorganic Nitrogen Fertilizer on Growth, Yield and Nitrogen Uptake of Black Rice”, Akta Agrosia, vol. 21, no. 2, pp. 55–60, Dec. 2018.