1. Deen S. M. (1977) Fundamentals of Database Systems (MacMillan), p 224.
2. CSPI (1978) MAXXIMUM Database management system: general information brochure (California Software Products, Inc, Santa Ana, California), p 44.
3. A minimal effort for maximal return philosophy applied to IGS onshore borehole records
4. Jeffery K. G. Gill E. M. (1975) Computer-based systems for geological field data.Pap. geol. Sum. Canada,No. 74-63, G-EXEC: a generalised FORTRAN system for data handling, pp 59–61.
5. Jensen K. Wirth N. (1978) PASCAL User Manual and Report (Springer-Verlag, New York), p 167.