Ramm, B. (1953). Types of apologetic systems: An introductory study to the Christian philosophy of religion. Van Kampen.
Lua i Stíl Chicago (17ú heag.)Ramm, Bernard. Types of Apologetic Systems: An Introductory Study to the Christian Philosophy of Religion. Wheaton: Van Kampen, 1953.
Lua MLA (9ú heag.)Ramm, Bernard. Types of Apologetic Systems: An Introductory Study to the Christian Philosophy of Religion. Van Kampen, 1953.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.