<hi xmlns="http://www.tei-c.org/ns/1.0" rend="bold">Bird, Steven, Edward Loper und Ewan Klein.</hi> 2009. <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#000000)italic">Natural Language Processing with Python.</hi> <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#000000)"> </hi> <hi xmlns="http://www.tei-c.org/ns/1.0" rend="color(#000000)">O’Reilly Media Inc.</hi>