Paudel, Deepak, et al. “The Effect of Pterygopalatine Fossa Block (PPFB) During Endoscopic Sinus Surgery (ESS) on Intraoperative Bleeding: A Randomized Control Trial”. Journal of BP Koirala Institute of Health Sciences, vol. 1, no. 2, Dec. 2018, pp. 35-41, doi:10.3126/jbpkihs.v1i2.22076.