1. Questionnaires in medicine. A guide to their design and use;Bennett, A.E.; Ritchie, K.,1975
2. Designing clinical research;Hulley, S.B.,1988
3. Measuring health. A guide to rating scales and questionnaires;McDowell, I.; Newell, C.,1987
4. Sales control by quantitative methods;Eastwood, R.P.,1940
5. Health surveys in practice and in potential: a critical review of their scope and methods;Cartwright, A.,1983