“AUTOMATIC SYSTEM FOR HAZARDOUS GAS, HUMAN DETECTION, TEMPERATURE MONITORING AND WATER LEVEL DETECTING IN COAL MINES USING GSM” (2023) International Journal of Engineering and Science Research, 13(3), pp. 1–9. Available at: https://www.ijesr.org/index.php/ijesr/article/view/984 (Accessed: 7 August 2025).