Adler, T. P., "Musical Dramas of Stephen Sondheim: Some Critical Approaches," in Pop Culture, Vol. 12, Winter 1978, pp. 513—25.

Adler looks at various critical approaches to Sondheim's musicals, focusing on the interplay of music and drama.

Bordman, Gerald, American Musical Theatre: A Chronicle, Oxford University Press, 1995.

Bordman presents a comprehensive examination of the musical from its origins to 1990.

Jones, John Bush, "From Melodrama to Tragedy: The Transformation of Sweeney Todd," in New England Theatre Journal, Vol. 1, No. 2, 1991, pp. 85—97.

Jones traces the development of the story of Sweeney Todd from its original version to the musical.

Schiff, Stephen, "Deconstructing Sondheim," in the New Yorker, Vol. 69, March 8, 1993, pp. 76—87.

Schiff discusses Sondheim's revolutionary modernist style and themes.