Harder, P. O. (1986). Basic materials in music theory: A programed course (6th ed.). Allyn and Bacon.
Lua i Stíl Chicago (17ú heag.)Harder, Paul O. Basic Materials in Music Theory: A Programed Course. 6th ed. Boston: Allyn and Bacon, 1986.
Lua MLA (8ú heag.)Harder, Paul O. Basic Materials in Music Theory: A Programed Course. 6th ed. Allyn and Bacon, 1986.
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