Koumanidou, C. Vakaki, M. Mazioti, A. Alexopoulou, E., Lower Esophageal Disorders in Childhood Evaluated by Transabdominal Ultrasound and Fluoroscopy: A Pictorial Essay, Canadian Association of Radiologists Journal, (69), 176-183, 2018, Canadian Medical Association, 0846-5371, 1488-2361