Elektronisk tilgjengelig
Bird, Steven., Ewan Klein and Edward Loper. Natural Language Processing with Python - Analysing Text with the Natural Language Toolkit. Updated for Python 3 and NLTK 3.
Tilgjengelig gratis: http://www.nltk.org/book/
evt. supplert av stoff fra denne:
Downey, Allen B. Think Python 2e. 2nd edition, Version 2.4.0. Massachusetts: Green Tea Press, 2015.
Tilgjengelig gratis: https://greenteapress.com/wp/think-python-2e/