Dead link to the book's first edition on the book's homepage

[IvDinten]

On the book's homepage, there is a reference link:

The first edition of the book, published by O'Reilly, is available at http://nltk.org/book_1ed/.

This link tries to go to http://nltk.org/book_1ed/, which returns an HTTP Status: 404 (not found).
When changed to use https://www.nltk.org/book_1ed/ or http://www.nltk.org/book_1ed/ it works.

Probably the automatic redirection stopped working (with non-www URLs).

Further, as it is likely related, going directly to http://nltk.org/book is also not being redirected to https://www.nltk.org/book/. Resulting in an HTTP Status: 404 (not found) when attempting. But http://www.nltk.org/book is being redirected to https://www.nltk.org/book/.