I'm wondering if anyone has any good recommendations for secondary sources on the nature and role of the figure of the sūta. Van Buitenen, in his introduction to the Bhagavadgītā, writes (1981, p. 5): "Traditionally the sūta, on the chariot of the warrior, is witness to the warrior's triumphs and occasional lapses; in danger he protects him. The triumphs of the warrior he celebrates in song, hence sūta also means 'bard.'" I'd like to read more about the details of this. Is there any good scholarship on it?