Irfan, M., Shabbir, M., Zahid, M., Hayat, A., & Majeed, S. M. I. (2015). A RANDOMIZED CONTROLLED CROSS-OVER TRIAL OF STANDARD ITALIAN PROTOCOL VERSUS FRONT-LOADED GLYCERYL TRINITRATE HEAD-UP TILT TEST. Pakistan Armed Forces Medical Journal, 65((SUPPL), S81-5. https://pafmj.org/PAFMJ/article/view/4418