Ziglar, Z. (2011). Better than Good. Jaico.
Lua i Stíl Chicago (17ú heag.)Ziglar, Zig. Better than Good. Jaico, 2011.
Lua MLA (9ú heag.)Ziglar, Zig. Better than Good. Jaico, 2011.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.