1. Veselago, V. G., "The electrodynamics of substances with simultaneously negative values of permittivity and permeability," Soviet Physics USPEKI, Vol. 10, No. 4, 509-514, 1968.
doi:10.1070/PU1968v010n04ABEH003699

2. Caloz, C. and T. Itoh, "Transmission line approach of left-handed (LH) materials and microstrip implementation of an artificial LH transmission line," IEEE Trans. Antennas Propagat., Vol. 52, No. 5, 1159-1166, 2004.
doi:10.1109/TAP.2004.827249

3. Mojahedi, M. and G. V. Eleftheriades, Negative Refraction Metamaterials: Fundamental Properties and Applications, 381-411, IEEE Press-Wiley Interscience, John Wiley & Sons Inc., 2005.

4. Mojahedi, M., E. Schamiloglu, K. Agi, and K. J. Malloy, "Frequency domain detection of superluminal group velocities in a distributed bragg reflector," IEEE Journal of Quantum Electronics, Vol. 36, 418424, 2000.

5. Mojahedi, M., K. J. Malloy, G. V. Eleftheriades, J. Woodley, and R. Y. Chiao, "Abnormal wave propagation in passive media," IEEE Journal of Selected Topics in Quantum Electronics, Vol. 9, 3039, 2003.

6. Woodley, J. and M. Mojahedi, "Negative group velocity in left-handed materials," Antennas and Prapagat. Society Symp., Vol. 4, 643-646, 2003.

7. Siddiqui, O. F., M. Mojahedi, and G. V. Eleftheriades, "Periodically loaded transmission line with effective negative refractive index and negative group velocity," IEEE Trans. Antennas Propagat., Vol. A51, No. 10, 2619-2625, 2003.
doi:10.1109/TAP.2003.817556

8. Mojahedi, M., E. Schamiloglu, K. Agi, and K. J. Malloy, "Frequency domain detection of superluminal group velocities in a distributed bragg reflector," IEEE Journal of Quantum Electronics, Vol. 36, No. 4, 418-424, 2000.
doi:10.1109/3.831016

9. Mojahedi, M. K., J. Malloy, G. V. Eleftheriades, J. Woodley, and R. Y. Chiao, "Abnormal wave propagation in passive media," IEEE Journal of Selected Topics in Quantum Electronics, Vol. 9, No. 1, 30-39, 2003.
doi:10.1109/JSTQE.2002.807971

10. Smith, D. R., W. J. Padilla, D. C. Vier, S. C. Nemat Nasser, and S. Schultz, "Composite medium with simultaneously negative permeability and permittivity," Physical Review Letters, Vol. 84, 4184-4187, 2000.
doi:10.1103/PhysRevLett.84.4184

11. Monti, G. and L. Tarricone, "Dispersion analysis of a planar negative-group velocity transmission line," Proc. 37th European Microwave Conf., 1644-1647, Munich, Germany, 2007.

12. Marqués, R., J. Mariel, F. Mesa, and F. Medina, "Left-handed simulation and transmission of EM waves in Subwavelength split-ring resonator-loaded metallic waveguide," Physical Review Letters, Vol. 89, No. 18, 2002.

13. Lubkowski, G., C. Damm, B. Bandlow, R. Schuhmann, M. Schüβler, and T. Weiland, "Waveguide miniaturization using spiral resonator and dipole arrays," Proc. 36th European Microwave Conf., 1312-1315, Manchester, UK, 2006.

14. Kondrat'ev, I. G. and A. I. Smirnov, "Comment on: `Left-handed simulation and transmission of EM waves in subwavelength split-ring resonator-loaded metallic waveguide' ," Physical Review Letters, Vol. 91, No. 24, 2003.

15. Yang, J., Q. Zhou, F. Zhao, X. Jiang, B. Howley, M. Wang, and R. T. Chen, "Characteristics of optical bandpass filters employing series-cascaded double-ring resonators," Optics Communications, Vol. 228, 91-98, 2003.
doi:10.1016/j.optcom.2003.09.092

16. Falcone, F., F. Martín, J., Bonache, R. Marqués, T. Lopetegi, and M. Sorolla, "Left handed coplanar waveguide bandpass filters based on bi-layer split ring resonators," IEEE Microw. Wirel. Compon. Lett., Vol. 14, No. 1, 10-12, Jan. 2004.
doi:10.1109/LMWC.2003.821512

17. García, J. G., F. Martín, F. Falcone, J. Bonache, I. Gil, T. Lopetegi, M. A. G. Laso, M. Sorolla, and R. Marqués, "Spurious passband suppression in microstrip coupled line bandpass filters by means of split ring resonators," IEEE Microw. Wirel. Compon. Lett., Vol. 14, No. 9, 416-418, Sep. 2004.
doi:10.1109/LMWC.2004.832066

18. Gil, I., J. Bonache, J. Garcia-Garcia, F. Falcone, and F. Martin, "Metamaterials in microstrip technology for filter applications," Antennas and Propagation Society International Symposium 2005, IEEE, Vol. 1, 668-671, 2005.
doi:10.1109/APS.2005.1551409

19. Al-Naib, I. A. I., C. Jansen, and M. Koch, "Miniaturized bandpass filter based on metamaterial resonators: A conceptual study," Journ. of Physics D: Applied Physics, Vol. 41, 205002, 2008.
doi:10.1088/0022-3727/41/20/205002

20. Lai, X., Q. Li, P. Y. Qin, B. Wu, and C.-H. Liang, "A novel wideband bandpass filter based on complementary split-ring resonator," Progress In Electromagnetics Research C, Vol. 1, 117-184, 2008.

21. Bahrami, H., M. Hakkak, and A. Pirhadi, "Analysis and design of highly compact bandpass waveguide filter using complementary split ring resonators (CSRR)," Progress In Electromagnetics Research, Vol. 80, 107-122, 2008.

22. Fan, J.-W., C.-H. Liang, and X.-W. Dai, "Design of cross-coupled dual-band filter with equal-length split-ring resonators," Progress In Electromagnetics Research, Vol. 75, 285-293, 2007.
doi:10.2528/PIER07060904

23. Zhang, J., B. Cui, S. Lin, and X.-W. Sun, "Sharp-rejection low-pass filter with controllable transmission zero using complementary split ring resonators (CSRRs)," Progress In Electromagnetics Research, Vol. 69, 219-226, 2007.
doi:10.2528/PIER06122103

24. García-García, J., F. Martín, J. D. Baena, R. Marqués, and L. Jelinek, "On the resonances and polarizabilities of split ring resonators," Journal of Applied Physics, Vol. 98, No. 3, 033103-033109, 2005.
doi:10.1063/1.2006224

25. Baena, J. D., R. Marqués, and F. Medina, "Artificial magnetic metamaterial design by using spiral resonators," Physical Review B, Vol. 69, 014402, 2004.
doi:10.1103/PhysRevB.69.014402

26. Monti, G. and L. Tarricone, "Gaussian pulse expansion of modulated signals in a double-negative slab," IEEE Trans. Microwave Theory and Tech., Vol. 54, No. 6, 2755-2761, 2006.
doi:10.1109/TMTT.2006.874879

27. Brillouin, L., Wave Propagation and Group Velocity, Academic, 1960.

28. Pendry, J. B., A. J. Holden, D. J. Robbins, and W. J. Stewart, "Magnetism from conductors, and enhanced non-linear phenomena," IEEE Trans. Microwave Theory and Tech., Vol. 47, No. 11, 2075-2084, 1999.
doi:10.1109/22.798002

29. Garrett, C. G. B. and D. E. McCumber, "Propagation of a gaussian light pulse through an anomalous dispersion medium," Physical Review A, Vol. 1, 305313, 1970.

30. Faxvog, F. R., C. Y. Chow, and T. Bieber J. A. Carruthers, "Measured pulse velocity greater than c in a neon absorption cell," Appl. Physics Letters, Vol. 17, No. 5, 1970.
doi:10.1063/1.1653360

31. Crisp, M. D., "Concept of group velocity in resonant pulse propagation," Physical Review A, Vol. 5, 2104-2108, 1971.
doi:10.1103/PhysRevA.4.2104

32. Bolda, E. L., R. Y. Chiao, and J. C. Garrison, "Two theorems for the group velocity in dispersive media," Physical Review A, Vol. 48, 3890, 1993.
doi:10.1103/PhysRevA.48.3890

33. Mitchell, M. W. and R. Y. Chiao, "Negative group delay and "fronts" in a causal system: An experiment with very low frequency bandpass amplifiers," Physics Letters A, Vol. 230, 133-138, June 1997.
doi:10.1016/S0375-9601(97)00244-2

34. Siddiqui, O. F., S. J. Erickson, and G. V. Eleftheriades, "Time-domain measurement of negative group delay in negative-refractive-index transmission-line metamaterials," IEEE Trans. Microwave Theory and Tech., Vol. 52, No. 5, 1449-1455, May 2004.
doi:10.1109/TMTT.2004.827018