Riggans, W. (1983). Numbers. Westminister.
Lua i Stíl Chicago (17ú heag.)Riggans, Walter. Numbers. Philadelphia: Westminister, 1983.
Lua MLA (9ú heag.)Riggans, Walter. Numbers. Westminister, 1983.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.