Natanael Bangun, et al. “Optimization of Drainage System on Jalan Sisingamangaraja to Overcome Flooding in Tigalingga Village, Dairi Regency”. Equivalent : Journal of Economic, Accounting and Management, vol. 4, no. 1, May 2026, pp. 1445-54, https://doi.org/10.61994/equivalent.v4i1.1830.