1Business Administration Department, Politeknik LP31, Medan, Indonesia.
2Faculty of Agriculture, Universitas Islam Sumatera Utara, Medan, Indonesia.
3Agribusiness Department, Faculty of Agriculture, Universitas Islam Sumatera Utara, Medan, Indonesia.
4Seed Center and Plantation Plant Protection (Balai Besar Perbenihan dan Proteksi Tanaman Perkebunan), Medan, Indonesia.
5Educational Office of Sumatera Utara (Dinas Pendidikan Sumatera Utara), Medan, Indonesia.
