Fortes, Y. M. L., E. Erudilho, T. S. da Silva, W. P. de O. Souza, and R. Silva-Neto. “Secondary Hypnic Headache: A Literature Review in the Last 34 Years”. Headache Medicine, vol. 13, no. 3, Oct. 2022, pp. 163-6, doi:10.48208/HeadacheMed.2022.15.