HAIDER, S Z, et al. “Comparison of Quincke and Pencil-Point Bevels in 25-G Needles Regarding Post Dural Puncture Headache in Caesarean Section”. Annals of King Edward Medical University, vol. 11, no. 2, Jan. 2021, pp. 81-82, doi:10.21649/akemu.v11i2.4238.