Human Immunodeficiency Virus Type 1 (Hiv-1) Strains Selected for Resistance Against the Hiv-1-Specific [2',5'-Bis-O-(Tert-Butyldimethylsilyl)-3'-Spiro- 5''-(4''-Amino-1'',2''-Oxathiole-2'',2''-Dioxide)]-Beta-D-Pentofurano Syl (Tsao) Nucleoside Analogues Retain Sensitivity to Hiv-1-Specific Nonnucleoside Inhibitors.