APA引文

Helm, P. (1973). The varieties of belief. Allen & Unwin [u.a.].

芝加哥风格引文

Helm, Paul. The Varieties of Belief. London [u.a.]: Allen & Unwin [u.a.], 1973.

MLA引文

Helm, Paul. The Varieties of Belief. Allen & Unwin [u.a.], 1973.

警告：这些引文格式不一定是100％准确.