IRAWAN, F. A. J. E.; WAHYUNI, A. 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, [S. l.], v. 27, n. 2, p. 10.21070/ijins.v27i2.2438, 2026. DOI: 10.21070/ijins.v27i2.2438. Disponível em: https://ijins.umsida.ac.id/index.php/ijins/article/view/2438. Acesso em: 15 oct. 2026.