1. The Munich Project CIP. Volume I: The Wide Spectrum Language CIP-L;Bauer,1985
2. Algorithmic Language and Program Development;Bauer,1982
3. Programming languages as abstract data types;Broy,1980
4. Partial abstract types;Broy;Acta Informat.,1982
5. Putting theories together to make specifications;Burstall,1977