1. Assoc. Prof., Dept. of Civ. Engrg., Lehigh Univ., Bethlehem, Pa.
2. Prof., Laboratoire D'Hydraulique, Ecole Polytechnique, Lausanne, Switzerland
3. Peter Bangsvej, Valby, Copenhagen, Denmark
4. Water Resources Engr., Dept. of Environmental, Water Planning and Management Branch, Burlington, Ontario