1. 2020 Topics and Objectives. 2011 Available from: http://www.healthypeople.gov/2020/topicsobjectives2020/default.aspx (cited April 2011).
2. Eiser C, Morse R . Can parents rate their child′s health-related quality of life? Results of a systematic review. Qual Life Res 2001; 10: 347–357.
3. WHO. Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19-22 June, 1946. In: Organization WH (ed.). Official Records of the World Health Organization, No. 2. WHO: Geneva, Switzerland, 1946, p 100.
4. CDC. Measuring healthy days: Population assessment of health-related quality of life. 2000 Available from: http://www.cdc.gov/hrqol/pdfs/mhd.pdf (cited April 2011).
5. McHorney CA . Health status assessment methods for adults: past accomplishments and future challenges. Annu Rev Public Health 1999; 20: 309–337.