P. H\aandlykken, and K. Nygaard. Software Engineering Environments Proceedings of the
Symposium held in Lahnstein, Germany, June 16-20, 1980, Amsterdam, North-Holland, (1981)
K. Nygaard. Information Processing, Proceedings from the IFIP 10th World Computer Congress, Dublin, Irland, September 1-5, 1986, Elsevier Science Publishers B.V., North Holland, (1986)
S. Briseid, T. Dokken, T. Hagen, and J. Nygaard. International Conference on Computational Science (4), volume 3994 of Lecture Notes in Computer Science, page 204-211. Springer, (2006)