Gardner, J. (1992). A Cappella: An anthology of unaccompanied choral music from seven centuries / Compiled and ed. by John Gardner. Oxford University Press.
Lua i Stíl Chicago (17ú heag.)Gardner, John. A Cappella: An Anthology of Unaccompanied Choral Music from Seven Centuries / Compiled and Ed. by John Gardner. Oxford [u.a.]: Oxford University Press, 1992.
Lua MLA (8ú heag.)Gardner, John. A Cappella: An Anthology of Unaccompanied Choral Music from Seven Centuries / Compiled and Ed. by John Gardner. Oxford University Press, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.