Singh, A., D. Joshi, R. Yadav, P. Sinha, V. Sharda, A. Yadav, S. Chaudhary, S. Kawale, G. Gupta, V. N. Mishra, R. N. Chaurasia, and A. Pathak. “Central Cognitive Processing Assessed by P300 in Migraine, Tension‑type Headache, and Cluster Headache”. International Journal of Clinical and Experimental Physiology, Vol. 2, no. 4, Oct. 2015, pp. 220-3, https://ijcep.org/index.php/ijcep/article/view/117.