Dalam musik, subjek adalah material, biasanya merupakan sebuah melodi yang dapat dikenal, yang menjadi dasar sebagian atau seluruh komposisi. Dalam wujud selain fuga, subjek dapat juga disebut sebagai tema.
Michel, François (ed). (1958–1961). Encyclopédie de la musique, 3 vols. Paris: Fasquelle. (Cited in Nattiez 1990.)
Nattiez, Jean-Jacques (1990). Music and Discourse: Toward a Semiology of Music, translated by Caroline Abbate [from Musicologie générale et sémiologie, 1987]. Princeton: Princeton University Press. ISBN0-691-09136-6 (cloth); ISBN0-691-02714-5.
Randel, Don Michael (ed.) (1999). The Harvard Concise Dictionary of Music and Musicians. Cambridge, Massachusetts: Belknap Press. ISBN0-674-00978-9.
Reti, Rudolph (1951). The Thematic Process in Music. London: Faber and Faber; New York: Macmillan Co. Reprinted, London: Faber and Faber, 1961, Westport, CT: Greenwoid Press, 1978. ISBN0-8371-9875-5.
Reti, Rudolph (1967). Thematic Patterns in Sonatas of Beethoven, edited by Deryck Cooke. London: Faber and Faber; New York: Macmillan Co. Reprinted, New York: Da Capo Press, 1992. ISBN0-306-79714-3.
Rushton, Julia (2001). "Subject Group". The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell. London: Macmillan Publishers.
Schoenberg, Arnold (1975). "My Evolution". In Style and Idea: Selected Writings of Arnold Schoenberg, edited by Leonard Stein, translated by Leo Black, 88. London: Faber and Faber. ISBN0-571-09722-7.