1. College of Economics and Management, Northeast Agricultural University, Harbin, Heilongjiang, China
2. Haikou University of Economics, Haikou, Hainan, China
3. Heilongjiang Agricultural Reclamation Management Cadre College, Harbin, China
4. International Cultural and Educational College, Northeast Agricultural University, Harbin, Heilongjiang, China
5. Facultad de Ciencias Adminsitrativas y Económicas, Universidad Tecnológica Indoamérica, Quito, Ecuador
6. Department of Mathematics, Government College Raigaon, Satna, Madhya Pradesh, India