Wall, J., & Caldwell, R. (1991). The Singer's voice: Breath. Pst...Inc.
Lua i Stíl Chicago (17ú heag.)Wall, Joan, agus Robert Caldwell. The Singer's Voice: Breath. Dallas, Tex: Pst...Inc, 1991.
Lua MLA (9ú heag.)Wall, Joan, agus Robert Caldwell. The Singer's Voice: Breath. Pst...Inc, 1991.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.