The Existence of Seed Resource Management Unit and Seed Grower to Support the Sustainable Certified Rice Seed in North Sumatera ProvinceDeddy Romulo Siagian, Novia Chairuman, Vivi Aryati, Siti Fatimah Batubara and Khasril AtrisiandyE3S Web Conf., 361 (2022) 04026DOI: https://doi.org/10.1051/e3sconf/202236104026