1. Report from the BSI Panel for the Standardization of VDM;Andrews,1988
2. The Dynamic Semantics of the BSI/VDM Specification Language;Arentoft,1988
3. Z Base Standard,1992
4. Specifications are not (necessarily) executable;Hayes;Software Eng. J.,1989
5. JCT1/SC22/WG13 ISO/IEC DIS 10514, Information technology-Programming languages-Modula-2.