References
- Covert , R. W. 1977 . Guidelines and criteria for constructing questionnaires Unpublished manuscript
- Dillman , D. A. 1978 . Mail and Telephone Surveys , New York : John Wiley & Sons .
- Windsor , R. A. , Baranowski , T. , Clark , N. and Cutter , G. 1984 . Evaluation of Health Promotion and Education Programs , Palo Alto , CA : Mayfield Publishing Company .