Percil, J., & Gray, J. (1988). Prospects: An advanced course teacher's book. Penguin Books.
Lua i Stíl Chicago (17ú heag.)Percil, John, agus Joanna Gray. Prospects: An Advanced Course Teacher's Book. London: Penguin Books, 1988.
Lua MLA (9ú heag.)Percil, John, agus Joanna Gray. Prospects: An Advanced Course Teacher's Book. Penguin Books, 1988.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.