Khanal, U. P., S. Paudel, and B. Lohani. “Ultrasonographic Measurement of Placental Thickness During Pregnancy As a Parameter For Estimating Gestational Age of The Foetus”. Nepalese Journal of Radiology, vol. 7, no. 1-2, Mar. 2018, pp. 13-18, doi:10.3126/njr.v7i1-2.19349.