Amino-acid co-variation in HIV-1 Gag subtype C: HLA-mediated selection pressure and compensatory dynamics. - Rolland, M; Carlson, J; Manocheewa, S; Swain, J; Lanxon-Cookson, E; Deng, W; Rousseau, C; Raugi, D; Learn, G; Maust, B; Coovadia, H; Ndung'u, T; et al. (PloS one, 2010)