APA (7th ed.) Citation

Siever, E., & Futato, D. (1997). Perl module reference. O'Reilly.

Chicago Style (17th ed.) Citation

Siever, Ellen, and David Futato. Perl Module Reference. Cambridge [etc.]: O'Reilly, 1997.

MLA (9th ed.) Citation

Siever, Ellen, and David Futato. Perl Module Reference. O'Reilly, 1997.