[1] Bohannon J 2006 Science 314 914
[2] Onnela J O, Saramaki J, Hyvonen J, Szabo G, Lazer D, Kaski K, Kertesz J, Barabasi A L 2007 PNAS 104 18
[3] Marta C G, Cesar A H, Barabasi A L 2008 Nature 453 7196
[4] Hong W, Han X P, Zhou T, Wang B H 2009 Chinese Phys. Lett. 26 2
[5] Ratti C, Williams S, Frenchman D, Pulselli R M 2006 EPB 33 5
[6] Reades J, Calabrese F, Sevtsuk A, Ratti C 2007 IEEE Pervas Comput 6 3
[7] Barabasi A L 2005 Nature 435 7039
[8] Vazquez A, Oliveira J, Dezso Z 2006 Phys. Rev. E 73 3
[9] Watts D, Strogatz S 1998 Nature 393 6684
[10] Musolesi M, Mascolo C 2007 Mobile Computing and Communications Review 11 3
[11] O’Neill E, Kostakos V, Kindberg T 2006 Ubiquitous Computing 4206 1
[12] Wigner E P 1967 SIAM Review 9 1
[13] Chen Z Q, Zheng R R, Chen H, Yao C Q 2000 Acta Phys. Sin. 49 5 (in Chinese) [陈志谦、 郑仁蓉、 陈 洪、 姚纯青 2000 物理学报 49 5]
[14] Chen Z Q, Zheng R R 2001 Chin. Phys. 10 12
[15] Li R, Yan P L, Chen J, Li J, Li J, Zhang K W, Zhong J X 2009 Acta Phys. Sin. 58 10 (in Chinese) [李 蓉、 颜平兰、 陈 健、 李 俊、 李 金、 张凯旺、 钟健新 2009 物理学报 58 10]
[16] Zhang F Z, Wang J, Gu Y 1999 Acta Phys. Sin. 48 12 (in Chinese) [张飞舟、 王 娇、 顾 雁 1999 物理学报 48 12]
[17] Xing Y Z, Xu G O 1999 Acta Phys. Sin. 48 5 (in Chinese) [邢永忠、 徐躬耦 1999 物理学报 48 5]
[18] Plerou V, Gopikrishnan P, Rosenow B, Amaral L A N, Guhr T 2002 Phys. Rev. E 65 6
[19] Yuan J, Mills K 2005 IEEE T DEPEND SECURE 2 4
[20] Sengupta A M, Mitra P P 1999 Phys. Rev. E 60 3