Non-response in telephone surveys of COPD patients does not introduce bias

Aanerud, M., Braut, H., Wentzel-Larsen, T., Eagan, T. M., & Bakke, P. S. (2013). Non-response in telephone surveys of COPD patients does not introduce bias. Journal of Telemedicine and Telecare, 19(1), 40-44. doi:10.1177/1357633X12474960