What is the ruling on selling educational notes that include paragraphs and questions from copyrighted textbooks?

It is not permissible to reprint or re-author publications for which the owners hold copyrights. However, merely benefiting from quoting something from those publications for citation is permissible if it is attributed to its owner and accuracy in نقل (transmission/citation) is ensured, because that is from the legally permissible اقتباس (quotation), even if the owner does not give permission. Sheikh Bakr Abu Zayd mentioned that quotation is a legitimate benefit that Muslims have practiced without objection, and an author's prohibition of it is considered a breach of consensus.