المؤلفون: Angel Atanasov Georgiev, Doroteya Shtereva-Tzouni, Tihomira Zlatanova
المصدر: International Scientific Publications, Bulgaria, Economy & Business Journal. 12(1):203-207
الإتاحة: https://ideas.repec.org/a/isp/journl/v12y2018i1p203-207.html