Wisudarti, C. F. R., Mahmud, and G. G. Mi’raj. “An Ultrasonography Guidance Lumbar Epidural Anaesthesia In Patient With Difficult Landmarks”. Jurnal Komplikasi Anestesi, Vol. 10, no. 1, May 2023, pp. 70-76, doi:10.22146/jka.v10i1.8329.