Uterocervical Angle Anterior, Posterior, and Cervical Length Ultrasound as a Predictors for Successful Delay in Labor of Pregnant Women with Threatened Preterm Birth (PTB), Akyuni, Qurrata, Sulistiyono Agus, Joewono Hermanto Tri, and Djuari Lilik , Pharmacognosy Journal, March 2023, Volume 15, Issue 1, p.52-56, (2023)