1. Students and teachers: A perspective on computer enhanced learning;Bell;The education magazine of Digital Equipment Corporation,1977
2. PPL: The pupils programming language;Ottevangers;Decus Europe, ninth seminar proceedings,1973
3. Problem solving by programming;van der Veer;Proceedings of the Digital Equipment Computer Users Society,1976
4. Notes on structured programming;Dijkstra;TH Eindhoven, dictaat No. 241,1969
5. Reducing programming errors in nested conditionals by prescribing a writing procedure;Sime;Int. J. Man-Machine Stud.,1977