APA استشهاد

Horst J Helle. (2015). The social thought of Georg Simmel. Sage.

استشهاد بنمط شيكاغو

Horst J Helle. The Social Thought of Georg Simmel. London: Sage, 2015.

MLA استشهاد

Horst J Helle. The Social Thought of Georg Simmel. Sage, 2015.