In practice, it is assumed that most URNs will refer to on-line resources, and that a mechanism will exist which takes a URN and returns a list of URLs[20]. Another, intriguing, possibility is that URNs may be linked to other URNs rather than directly to URLs. This raises the prospect of their being used to establish a semantic network of pointers to resources - a true virtual library!
M.V. Simkin, V.P. Roychowdhury
Scientists often re-invent things which were long known. Here we review these activities as related to the mechanism of producing power law distributions, originally proposed in 1922 by Yule to explain experimental data on the sizes of biological genera, collected by Willis. We estimate that scientists are busy re-discovering America about 2/3 of time.