Valverde, M., Madrid, R., García, A. L., Del Amor, F. M. and Rincón, L. F. (2013) “Use of almond shell and almond hull as substrates for sweet pepper cultivation. Effects on fruit yield and mineral content”, Spanish Journal of Agricultural Research, 11(1), pp. 164-172. doi: 10.5424/sjar/2013111-3566.