1. Department of Internal Medicine; University of Iowa; Iowa City IA USA
2. Division of Pulmonary, Critical Care and Occupational Medicine; University of Iowa; Iowa City IA USA
3. Ruth Lilly Medical Library; Indiana University; Indianapolis IN USA
4. Division of Pulmonary and Critical Care Medicine; University of Maryland; Baltimore MD USA
5. Division of Gastroenterology and Hepatology; University of Iowa; Iowa City IA USA