Life cycle assessment and eco-efficiency Indicator for ulos weaving using loom machine in Toba Samosir Regency of North SumatraYuli Yanthi Siagian, Rizal Sinaga, Christoper Sinaga and Yosef ManikE3S Web Conf., 74 (2018) 05002DOI: https://doi.org/10.1051/e3sconf/20187405002