[1]
M. G. J. van den Brand, N. W. P. van Diepen, E. A. Boiten, C. H. A. Koster, H. A. Partsch, and N. Völker, “USTOPIA REQUIREMENTS THOUGHTS ON A USER-FRIENDLY SYSTEM FOR TRANSFORMATION OF PROGRAMS IN ABSTRACTO”, Period. Polytech. Elec. Eng., vol. 35, no. 2, pp. 101–123, Jan. 1991.