Simatupang, Frengki, et al. “A Web-Based Navigation Control System for Lake Toba Cleaning Using NodeMCU ESP8266 and Pulse Width Modulation (PWM)”. Piston: Journal of Technical Engineering, vol. 9, no. 1, Aug. 2025, pp. 40-53, doi:10.32493/pjte.v9i1.51670.