F. García Vallejo, R. Bonilla, G. Gallego, M. T. Rugeles, and I. Borrero, “Amplification of human lymphotropic virus 1 (HTLV-1) DNA segments in patients with tropical spastic paraparesis and asymptomatic seropositive patients”, Colomb Med, vol. 23, no. 2, pp. 50–56, Jun. 1992.