. "Trouble" . . . . . "''Circus''" . . "Circus (Britney Spears album)" . . . . . . . . . . . . . . . . "Circus" . . . . . . . . . . . . . . . . . . . . . . . "Circus (Britney Spears album)" . . . . . . . "Circus_(Britney_Spears_album)" . . "''Circus'' (Britney Spears album)" . . . . . "sixth studio album of the same name." . .