Awad, Ali Ismail: 'Introduction to information security foundations and applications' (Security, 2018), 'Information Security: Foundations, Technologies and Applications', Chap. 1, pp. 3-11, DOI: 10.1049/PBSE001E_ch1
IET Digital Library, https://digital-library.theiet.org/;jsessionid=392hjpqmi6tpr.x-iet-live-01content/books/10.1049/pbse001e_ch1