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Research: Effect of survey instrument on participation in follow-up: a RCT of questionnaire versus telephone interview http://t.co/xlFp9WBO
Research: Effect of survey instrument on participation in follow-up: a RCT of questionnaire versus telephone interview http://t.co/xlFp9WBO
Effect of survey instrument on participation in a follow-up study: a randomization study of a mailed questionnaire v... http://t.co/P4yW9Clw