Fayyaz, H., Ambreen, S., Raziq, H. and Hayyat, A. 2021. Comparison of cortisol levels in patients with vasovagal syncope and postural tachycardia syndrome. Pakistan Journal of Medical Sciences. 38, 1 (Nov. 2021). DOI:https://doi.org/10.12669/pjms.38.1.4122.