I think you should elaborate a bit since it might not be clear to US readers. College professors (collaboratively) write teaching materials that are copied and

I think you should elaborate a bit since it might not be clear to US readers. College professors (collaboratively) write teaching materials that are copied and bound by the print shop of your school. Nowadays they're typically freely available in PDF, to registered students at least. Nothing like American textbooks sold over $100 by big publishing companies.