159, 56-63 (1968). (3) تحقيق الثراء يمكن أن يكون عسيرا

Empirical evidence (mostly) for and (occasionally) against the prevalence of scale-free networks has appeared in a number of places. Some of the more interesting papers are as follows: ⋆⋆ Amaral, L. A. N., Scala, A., Barthelemy, M., and Stanley, H. E. Classes of behavior of small-world networks.

Sciences,

97, 11149-11152 (2000). ⋆⋆ Adamic, L. A., and Huberman, B. A.

Science,

287, 2115a (2000). ⋆⋆ Barabási, A. L., Albert, R., Jeong, H., and Bianconi, G. Power-law distribution of the World Wide Web,

Science,

287, 2115b (2000). ⋆⋆ Faloutsos, M., Faloutsos, P., and Faloutsos, C. On power-law relationships of the Internet topology.

Computer Communication Review,

29, 251-262 (1999). ⋆⋆ Liljeros, F., Edling, C. R., Amaral, L. A. N., Stanley, H. E., and Aberg, Y. The web of human sexual contacts.

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