Borja Padilla, R., A. Martín Martín, and J. A. Fiestas de Ursinos. “Influence of Substrate Concentration on the Kinetics of Olive Mill Wastewater Biomethanation in Fluid Bed Bioreactors Using Immobilized Microorganisms”. Grasas Y Aceites, vol. 42, no. 5, Oct. 1991, pp. 363-70, doi:10.3989/gya.1991.v42.i5.1221.