Springer, J. M. (1909). The heart of central Africa: Mineral wealth and missionary opportunity. Methodist Book Concern.
Lua i Stíl Chicago (17ú heag.)Springer, John McKendree. The Heart of Central Africa: Mineral Wealth and Missionary Opportunity. New York: Methodist Book Concern, 1909.
Lua MLA (8ú heag.)Springer, John McKendree. The Heart of Central Africa: Mineral Wealth and Missionary Opportunity. Methodist Book Concern, 1909.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.