Trends in antiretroviral drug resistance and clade distributions among HIV-1-infected blood donors in Sao Paulo, Brazil - Barreto, Claudia C; Nishyia, Anna; Araújo, Luciano Vieira de; Ferreira, João Eduardo; Busch, Michael P; Sabino, Ester Cerdeira (JAIDS Journal of Acquired Immune Deficiency Syndromes, 2006)