Connolly, T. M. and Beg, C. E. (2015) Database systems: a practical approach to design, implementation, and management. Sixth edition. Harlow, Essex, England: Pearson. Available at: https://ebookcentral.proquest.com/lib/uea/detail.action?docID=5136720.
Van der Lans, R. F. (2006) Introduction to SQL: mastering the relational database language. 4th ed. Upper Saddle River, N.J.: Addison-Wesley.