1Oil Technology Services, Inc., 10700 Northwest Freeway, Suite 455, Houston, TX 77092-7316, USA
2Department of Radiology, Henry Ford Hospital, 2799 W. Grand Blvd. Detroit, MI 48202-2689, USA
3Epidemiology and Biometrics, Dow Corning Corporation, P. O. Box 994, Mail dCO1120, Midland, MI 48686-0994, USA
4Department of Mathematics, Albion College, 4803 Kellogg Center, Albion, MI 49224-5013, USA
5Breech Research Laboratory, Bone and Joint Center, Henry Ford Hospital, 2799 W. Grand building, Detroit, MI 48202-2689, USA