s151.
Albert-László Barabási (2002), Linked, chapters 2, 6 and 7; and Mark Newman, Albert-László Barabási and Duncan J. Watts (2006), The Structure and Dynamics of Networks, pp 9–19, pp 229–239 and on pp 349–352 a reprinting of Albert-László Barabási and Réka Albert, “Emergence of Scaling in Random Networks”, originally in Science, vol 286, 1999, pp 509–512. For a summary, see also Thomas Homer-Dixon (2006), The Upside of Down, chapter 5, especially pp 116–120. Diagram from Wikimedia Commons, used under the GNU Free Documentation License. Image available at https://tinyurl.com/o7d3zae .