A. Madoz-Gúrpide, E. Barbudo del Cura, M. Leira Sanmartín, M. Navío Acosta, L. Villoria Borrego, and E. Ochoa Mangado, “Addiction characteristics as prognostic factors in opiate dependence treated with naltrexone”, Actas Esp Psiquiatr, vol. 32, no. 4, pp. 199–210, Jul. 2004.