Holle, D., Burmeister, J., Scherag, A., Ose, C., Diener, H., & Obermann, M. (2013). Study protocol of Prednisone in episodic Cluster Headache (PredCH): A randomized, double-blind, placebo-controlled parallel group trial to evaluate the efficacy and safety of oral prednisone as an add-on therapy in the prophylactic treatment of episodic cluster headache with verapamil. BioMed Central.

Holle, Dagny, Jan Burmeister, André Scherag, Claudia Ose, Hans-Christoph Diener, und Mark Obermann. Study Protocol of Prednisone in Episodic Cluster Headache (PredCH): A Randomized, Double-blind, Placebo-controlled Parallel Group Trial to Evaluate the Efficacy and Safety of Oral Prednisone As an Add-on Therapy in the Prophylactic Treatment of Episodic Cluster Headache With Verapamil. BioMed Central, 2013.

Holle, Dagny, et al. Study Protocol of Prednisone in Episodic Cluster Headache (PredCH): A Randomized, Double-blind, Placebo-controlled Parallel Group Trial to Evaluate the Efficacy and Safety of Oral Prednisone As an Add-on Therapy in the Prophylactic Treatment of Episodic Cluster Headache With Verapamil. BioMed Central, 2013.