1. Professor and Chair, Dept. of Civil Engineering, Ryerson Univ., Toronto, ON, Canada M5R 2K3.
2. Assistant Professor, Dept. of Geography, Univ. of Northern Iowa, Sabin 1, Cedar Falls, IA 50614.
3. Assistant Professor, Dept. of Civil and Environmental Engineering, Carleton Univ., Ottawa, ON Canada K1S 5B6.
4. Associate Professor, Dept. of Civil and Construction Engineering, Iowa State Univ., Ames, IA 50011.