What is the author's style in Swing Low Sweet Chariot ?

As pointed out by John Wesley Work in his book American Negro Songs and Spirituals, African­American songs often retain forms that originated in African tribal customs. "Swing Low Sweet Char­iot" belongs to the largest group, a class of spiri­tuals that use the African "call and response chant form." Work described it as "interesting as well as distinctive. Its feature is a melodic fragment sung repeatedly by the chorus as an answer to the chal­lenging lines of the leader which usually change."