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Cook, J., JA Cook, E. Bongard, C. Heneghan, and CC Butler. Conditional Versus Non-conditional Incentives to Maximise Return of Participant Completed Questionnaires in Clinical Trials: A Cluster Randomised Study Within a Trial. BioMed Central, 2023.

Cook, J., et al. Conditional Versus Non-conditional Incentives to Maximise Return of Participant Completed Questionnaires in Clinical Trials: A Cluster Randomised Study Within a Trial. BioMed Central, 2023.