How to disable "buy" URL

Theming
1

I have a webbook that is freely accessible. However PressBooks still generates a URL in the form

https://my.website.org/title-of-book/buy/

This web pages says “BUY THE BOOK It’s coming”

Although there is no link to this URL, Google sees it and it appears in Google search results.

Is there a way to prevent this URL from being generated?

Thanks.

2

in your robots.txt

#google close pages
User-agent: *
Disallow: /buy/

that is my robots.txt

#google close pages
User-agent: *
Disallow: /front-matter/*
Disallow: /back-matter/*
Disallow: /h5p-listing/
Disallow: /authors/
Disallow: /buy/
Disallow: /access-denied/
Disallow: /chapter/null-*