APA (7th ed.) Citation

Pickering, W. H. (1960). History of the cluster system. [publisher not identified].

Chicago Style (17th ed.) Citation

Pickering, William H. History of the Cluster System. [Place of publication not identified]: [publisher not identified], 1960.

MLA (9th ed.) Citation

Pickering, William H. History of the Cluster System. [publisher not identified], 1960.