http://ds.knu.edu.ua/jspui/bitstream/123456789/3127/1/%D0%A8%D0%B0%D0%BF%D0%BE%D0%B2%D0%B0%D0%BB%D0%BE%D0%B2%20%D0%92.%20%D0%90.%20%D0%97%D0%B0%D0%B1%D0%B5%D0%B7%D0%BF%D0%B5%D1%87%D0%B5%D0%BD%D0%BD%D1%8F%20%D0%BE%D1%85%D0%BE%D1%80%D0%BE%D0%BD%D0%B8%20%D0%BF%D1%80%D0%B0%D1%86%D1%96.pdf