Macfarren, G. A., & Oxenford, J. (1864). Helvellyn: An opera in four acts. Cramer.
Lua i Stíl Chicago (17ú heag.)Macfarren, G. A., agus John Oxenford. Helvellyn: An Opera in Four Acts. London: Cramer, 1864.
Lua MLA (8ú heag.)Macfarren, G. A., agus John Oxenford. Helvellyn: An Opera in Four Acts. Cramer, 1864.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.