Ensel, Gustavus S. Ancient Liturgical Music. A Comparative and Historical Essay on the Origin & Development of Sacred Music from the earliest times, with illustrations of the music employed in the worship of the Synagogue, Church & Mosque. Paducah, Ky., c1880. 230 p.
Ensel, Gustavus S. “Traditional Music of the Synagogue.” In: Official Report of the Eleventh Annual Meeting of the Music Teacher’s National Association, held at Indianapolis, Ind., July 5, 6, 7, 8, 1887 ([n.p., 1887?]), pp. 123-29.