<ref name=WS>{{Cite journal | last1 = Watts | first1 = D. J. | authorlink1 = | last2 = Strogatz | first2 = S. H. | authorlink2 = | title = Collective dynamics of 'small-world' networks | journal = Nature | volume = 393 | issue = 6684 | pages = 440–442 | doi = 10.1038/30918 | year = 1998 | url = http://worrydream.com/refs/Watts-CollectiveDynamicsOfSmallWorldNetworks.pdf | pmid = 9623998 | pmc = | bibcode = 1998Natur.393..440W }}</ref> | <ref name=WS>{{Cite journal | last1 = Watts | first1 = D. J. | authorlink1 = | last2 = Strogatz | first2 = S. H. | authorlink2 = | title = Collective dynamics of 'small-world' networks | journal = Nature | volume = 393 | issue = 6684 | pages = 440–442 | doi = 10.1038/30918 | year = 1998 | url = http://worrydream.com/refs/Watts-CollectiveDynamicsOfSmallWorldNetworks.pdf | pmid = 9623998 | pmc = | bibcode = 1998Natur.393..440W }}</ref> |