Exemption; gross receipts tax; sale of textbooks from

certain bookstores to enrolled students. Exempted from the gross receipts tax are the receipts from the sale of textbooks and other materials that are required for courses at a public post-secondary educational institution if the sale is by a bookstore located on the campus of the institution and operated pursuant to a contractual agreement with that institution and the sale is to a student enrolled at the institution who displays a valid student identification card.