Nucleoside reverse-transcriptase inhibitor cross-resistance and outcomes from second-line antiretroviral therapy in the public health approach: an observational analysis within the... by Paton, N, Kityo, C, Thompson, J, Nankya, I, Bagenda, L, Hoppe, A, Hakim, J, Kambugu, A, van Oosterhout, J, Kinconco, M, Bertagnolio, S, Easterbrook, P, Mugyenyi, P, Walker, A