//-->
Searching for a common currency: Critical appraisal of the scientific basis underlying European harmonization of the measurement of health related quality of life (EuroQol(c))
Gafni, Amiram, (1993)
Economics and the evaluation of health care programmes: generalisability of methods and implications for generalisability of results
Birch, Stephen, (2003)
Cost-effectiveness ratios: in a league of their own
Birch, Stephen, (1994)