FitzGerald, Jerry, et al. Business Data Communications and Networking. Twelfth edition, Wiley, 2015, http://catalogimages.wiley.com/images/db/jimages/9781118891681.jpg.
---. Business Data Communications and Networking. Twelfth edition, Wiley, 2015.
Perlman, Radia. ‘An Algorithm for Distributed Computation of a Spanningtree in an Extended LAN’. Proceedings of the Ninth Symposium on Data Communications - SIGCOMM ’85, ACM Press, 1985, pp. 44–53, https://doi.org/10.1145/319056.319004.
Shay, William A. Understanding Data Communications and Networks. 3rd ed, Thomson Brooks/Cole, 2004.