Spencer, S. (2009). The Heart of leadership. Bhuana Ilmu Populer.
Lua i Stíl Chicago (17ú heag.)Spencer, Sabina. The Heart of Leadership. Bhuana Ilmu Populer, 2009.
Lua MLA (8ú heag.)Spencer, Sabina. The Heart of Leadership. Bhuana Ilmu Populer, 2009.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.