University of Minnesota, Minneapolis, Minnesota, United States
National Jewish Medical and Research Center, Denver, Colorado, United States
University of Alabama at Birmingham, Birmingham, Alabama, United States
Veteran's Administration Medical Center, Minneapolis, Minnesota, United States
University of Minnesota Medical Center, Minneapolis, Minnesota, United States
Tobacco Use Research Center, University of Minnesota, Minneapolis, Minnesota, United States
Case Western Reserve University, Cleveland, Ohio, United States
Ohio State University, Columbus, Ohio, United States
Columbia University Medical Center, New York, New York, United States
University of Minnesota, Minneapolis, Minnesota, United States
University of Minnesota, Minneapolis, Minnesota, United States
University of Minnesota - St. Paul Campus, Saint Paul, Minnesota, United States
St. Mary's Medical Center, Duluth, Minnesota, United States