Development of an arable layer: a key concept for better management of infertile tropical savanna soils - Amézquita Collazos, Edgar; Rao, Idupulapati M.; Hoyos Garcés, Phanor; Molina López, Diego Luis; Chávez, Luis F.; Bernal Riobo, Jaime Humberto (Springer, 2007)