Irawan, Fila Atma Jalu Eka, and Atik Wahyuni. 2026. “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 (2):10.21070/ijins.v27i2.2438. https://doi.org/10.21070/ijins.v27i2.2438.