When we do higher graduation, we tend to take specialized courses which may be focus only on one particular area of study. For example, if you take commerce then you will be learning only subjects closely related to commerce and may not include science or mathematics in them. And the study would be a very detailed study on the subject which may cover all most all core areas of the subject.

At this juncture, it may not be possible for the university to stick to one book for the course material. They would suggest the students to refer lot of books for the study of the subject. Students generally pick up the reference books from the library. But they cannot keep the book for long since they have taken the book on lending. They tend to photocopy the pages required.

For example, if you are going to write social work exam, then the subject topics would be from various books and you may have to refer atleast few of them. The students take photocopy of whatever they could study and make it their course material or get it from their senior students. The students also refer to websites for information on books and course materials.