Rafiq, R., Prins, H. J., Boersma, W. G., Daniels, J. M., den Heijer, M., Lips, P., & de Jongh, R. T. (2017). Effects of daily vitamin D supplementation on respiratory muscle strength and physical performance in vitamin D-deficient COPD patients: A pilot trial. Int J Chron Obstruct Pulmon Dis.

Rafiq, Rachida, Hendrik J. Prins, Wim G. Boersma, Johannes MA Daniels, Martin den Heijer, Paul Lips, und Renate T. de Jongh. "Effects of Daily Vitamin D Supplementation On Respiratory Muscle Strength and Physical Performance in Vitamin D-deficient COPD Patients: A Pilot Trial." Int J Chron Obstruct Pulmon Dis 2017.

Rafiq, Rachida, et al. "Effects of Daily Vitamin D Supplementation On Respiratory Muscle Strength and Physical Performance in Vitamin D-deficient COPD Patients: A Pilot Trial." Int J Chron Obstruct Pulmon Dis 2017.