APA (7th ed.) Citation

Clarkson, P. S. (1938). A bibliography of William Sydney Porter (O. Henry). The Caxton printers, ltd..

Chicago Style (17th ed.) Citation

Clarkson, Paul Stephen. A Bibliography of William Sydney Porter (O. Henry). Caldwell, Idaho: The Caxton printers, ltd., 1938.

MLA (8th ed.) Citation

Clarkson, Paul Stephen. A Bibliography of William Sydney Porter (O. Henry). The Caxton printers, ltd., 1938.