Irawan, Fila Atma Jalu Eka, and Atik Wahyuni. “Cost And Productivity Analysis Of Installing 40 X 60 X 120 U-Ditches Using Heavy Equipment Compared To Manual Methods In Sumur Welut, Lakarsantri District, Surabaya: Analisis Biaya Dan Produktivitas Pemasangan U-Ditch 40 X 60 X 120 Menggunakan Alat Berat Dibandingkan Metode Manual Di Sumur Welut, Kec. Lakarsantri, Surabaya”. Indonesian Journal of Innovation Studies 27, no. 2 (October 13, 2026): 10.21070/ijins.v27i2.2438. Accessed October 15, 2026. https://ijins.umsida.ac.id/index.php/ijins/article/view/2438.