Energy-efficient multi-agent hybrid GNN-XGBoost framework for IoT-enabled smart grid management with blockchain-secured urban energy sustainability. - Gv. Shrichandran; K. Indhumathi; Sultan Ahmad; Tahani Alsubait; Eatedal Alabdulkreem; Shamimul Qamar; Hashim El Shafie; Mohamed Uvaze Ahamed Ayoobkhan (Sustain. Comput. Informatics Syst., 2026)