[1] Era soft (Computerized Solutions for your Business), “SQL Lecture 1,” 5 May 2007. http://www.erasoft.edu.pk/
[2] Online Help for Microsoft SQL Enterprise Manager, Microsoft Corporation, Version: 7.0.
[3] E. S. Zhou, C. X. Xu, H. Wu, J. Zhang, Y. H. Lin, J. Q. Wang and J. Gray, “E-R Modeler: A Database Modeling Toolkit,” Barrett Bryant Department of Computer and Information Sciences, University of Alabama at Birmingham, Birmingham, 2-3 April 2004.
[4] Terry Quatrani, Visual Modeling with Rational Rose 2000 and UML, Addison-Wesley Professional, 27 October 1999.
[5] E. F. Codd, “A Relational Model of Data for Large Shared Data Banks,” Communications of the ACM, Vol. 13, No. 6, 1970, pp. 377-387. doi:10.1145/362384.362685