Burhan Abdullah, Q., Abdulghani Alabady, S., M. Salleh, F. and S. Khan, M. 2025. A Review of Hierarchical Routing Protocols in Wireless Sensor Networks: Types and Recent Developments. Al-Rafidain Engineering Journal (AREJ). 30, 2 (Sep. 2025), 1–15. DOI:https://doi.org/10.33899/arej.2025.157162.1387.