Khan, Humaira Fayyaz, et al. “SHORT DURATION HEAD-UP TILT TEST: A COMPARISON WITH CONVENTIONAL LONG PROTOCOL IN PATIENTS OF ORTHOSTATIC INTOLERANCE”. Journal of Ayub Medical College Abbottabad, vol. 22, no. 4, Dec. 2010, pp. 78-80, https://jamc.ayubmed.edu.pk/index.php/jamc/article/view/2714.