@article{article3614877a,
title   = {Prevalence of negative sliding sign representing pouch of Douglas obliteration during pelvic transvaginal ultrasound for any indication},
author = {Leonardi, M. and Martins, Wellington de Paula and Espada, M. and Georgousopoulou, E. and Condous, G.},
year = {2020},
doi = {10.1002/uog.22023},
journal   = {Ultrasound in Obstetrics and Gynecology}
}