Nested Named-Entity Recognition on Vietnamese COVID-19: Dataset and Experiments. - Ngoc C. Lê; Hai-Chung Nguyen-Phung; Thu-Huong Pham Thi; Hue Vu; Phuong-Thao Nguyen Thi; Thu-Thuy Tran; Hong-Nhung Le Thi; Thuy-Duong Nguyen-Thi; Thanh-Huy Nguyen (CoRR, 2025)