1. J. Abbink, A. Beulens et al., Discussion paper: The construction of the interface between ORACLE and MGG, ORES bv. June 1985.
2. J.L. Bennett, Analysis and design of the user interface for decision support systems, in:Building Decision Support Systems, ed. J.L. Bennett (Addison Wesley, Reading, Ma, 1983).
3. A. Beulens and J. van Nunen, On using quantitative methods in decision support systems: design and implementation issues, in:Operations Research Proceedings 1984 (Springer Verlag, Berlin/Heidelberg 1985).
4. A. Beulens and J. van Nunen, Decision support systems and expert systems, Working Paper, Rotterdam School of Management, 1986.
5. C.J. Date,An Introduction to Database Systems, Vol. I, Fourth Edition (Addison Wesley, 1986).