A. K. . Gana, B. . Apuyor, and E. . Samuel, “Determination of Appropriate Rate of Cattle Dung for Effective Weed Control and Higher Yield of Castor Bean Seed (Ricinus Communis L) At Badeggi, Nigeria”, Glob. J. Bot. Sci., vol. 3, no. 1, pp. 1–6, Dec. 2015.