Mutual learning approach for improving river discharge predictability in data-scarce regions: a case study in the Cau River Basin, Vietnam - Nguyen Thi Thu Ha; Duc Quang Vu; Ngoc Phu Doan; Ly Tran Tan; Phan Pham Chi Mai; Dao Duy Minh; Zichi Zhang; Viet-Hung Tran; Ngoc Anh Le; Nguyen Hao Quang; Minh Quan Dang; Mai Thai Son (Environmental and Ecological Statistics, 2026)