Irawan, F. A. J. E., & Wahyuni, A. (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