"Figure 9-1: Basic communication" (page 187), Nayak, U., & Rao, U. H. (2014). The InfoSec handbook: An introduction to information security (1st ed.). APRESS.
"Figure 9-3: Computer communication" (page 189), Nayak, U., & Rao, U. H. (2014). The InfoSec handbook: An introduction to information security (1st ed.). APRESS.