Helm, P. (1987). Objective knowledge: A christian perspective. Inter-varsity press.
芝加哥风格引文Helm, Paul. Objective Knowledge: A Christian Perspective. Leicester: Inter-varsity press, 1987.
MLA引文Helm, Paul. Objective Knowledge: A Christian Perspective. Inter-varsity press, 1987.
警告：这些引文格式不一定是100％准确.