Cita APA (7a ed.)

Bird, S., Klein, E., & Loper, E. (2009). Natural language processing with Python. O'Reilly.

Cita Chicago Style (17a ed.)

Bird, Steven, Ewan Klein, y Edward Loper. Natural Language Processing with Python. Beijing [etc.]: O'Reilly, 2009.

Cita MLA (9a ed.)

Bird, Steven, et al. Natural Language Processing with Python. O'Reilly, 2009.