1. Podlubny, I. Fractional Differential Equations, Academic Press, New York (1999)
2. Kilbas, A. A., Sarivastava, H. M., and Trujillo, J. J. Theory and Applications of Fractional Differential Equations, Elsevier, New York (2006)
3. Mainardi, F. Fractional Calculus and Waves in Linear Viscoelasticity, Imperial College Press, London (2010)
4. Sheu, L. J., Chen, H. K., Chen, J. H., and Tam, L. M. Chaotic dynamics of the fractionally damped Duffing equation. Chaos, Solitons and Fractals, 32(4), 1459–1468 (2007)
5. Ge, Z. M. and Ou, C. Y. Chaos synchronization of fractional order modified Duffing systems with parameters excited by a chaotic signal. Chaos, Solitons and Fractals, 35(2), 705–717 (2008)