Sanchez, P.A.; Logan, T.J. (1992). "Myths and science about the chemistry and fertility of soils of the tropics"(PDF). Dalam Lal, R; Sanchez, P.A. Myths and Science of Soils of the Tropics. Madison, Wisconsin: Soil Science Society of America. hlm. 36. Diakses tanggal 14 Juni 2014.Pemeliharaan CS1: Banyak nama: editors list (link)