1. SIMULA 67, common base language;Dahl,1967
2. Smalltalk-80: The Language and its Implementation;Goldberg,1983
3. Objects and Things,1987
4. Dialogue cells: A method for defining interactions;Kuhlmann,1982
5. Input-output tools: A language facility for interactive and real-time systems;Van Den Bos;IEEE Transactions on Software Engineering,1983