1. Crossing the quality chasm: a new health system for the 21st century. Committee on Quality of Health Care in America;Institute of Medicine,2001
2. Complexity science. The challenge of complexity in health care;Plsek;BMJ,2001
3. Flies without wings;Verbrugge,2005
4. Aging in the eighties: the prevalence of comorbidity and its association with disability. Advance Data From Vital and Health Statistics;Guralnik,1989
5. Anderson G. Testimony before the Subcommittee on Health of the House Committee on Ways and Means. Hearing on Promoting Disease Management in Medicare; 2002: Available at: http://waysandmeans.house.gov. Accessed June 2006.