@article{Aznar:150414,
      author        = "Aznar, M. and Manyà, J. J. and García, G. and Sánchez,
                       J.L. and Murillo, M. B.",
      title         = "{Influence of freeboard temperature, fluidization velocity
                       and particle size on tar production and composition during
                       the air gasification of sewage sludge}",
      year          = "2008",
}