• https://libeldoc.bsuir.by/handle/123456789/25027
• https://libeldoc.bsuir.by/handle/123456789/48750
• https://libeldoc.bsuir.by/handle/123456789/26668
• https://libeldoc.bsuir.by/handle/123456789/50980
• https://libeldoc.bsuir.by/handle/123456789/8177
• https://libeldoc.bsuir.by/handle/123456789/3498