Copyright law gives protection both to the person creating a work, and to the work itself. A work can be text, music, image, website, etc.
In addition, copyright ensures that artists, writers, etc., obtain a revenue from their work in order that they can continue to create new textbooks, art, etc.
Moreover, it motivates publishers, companies, and distributors to invest in the development and production of new books and cultural products. Thus, copyright ensures increased cultural diversity and development in Denmark.
If all authors (and translators) of the work have been dead for more than 70 years, then the copyright protection have expired and you are permitted to use the text without page limitations.
Copyright is a complicated set of rules that can be difficult to navigate through. You can, therefore, easily perform an illegal action without being aware of it.
You should pay particular attention to the context in which you use any material. Is it only for private use, or is it material that you are going to be sharing with others, your fellow students for example?