T. A. Ngo and H. T. V. Bui, “Biohydrogen Production Using Immobilized Cells of Hyperthermophilic Eubacterium Thermotoga neapolitana on Porous Glass Beads”, J. Technol. Innov. Renew. Energy, vol. 2, no. 3, pp. 231–238, Aug. 2013.