1. Miller, K.S. and Ross, B. (1993) An Introduction to Fractional Calculus and Fractional Differential Equations. John Wiley and Sons, New York.
2. Podlubny, I. (1999) Fractional Differential Equations. An Introduction to Fractional Derivatives, Fractional Differential Equations, to Methods of Their Solutions and Some of Their Applications. Mathematics in Science and Engineering, Vol. 198, Academic Press, San Diego.
3. Kilbas, A.A., Srivastava, H.M. and Trujillo, J.J. (2006) Theory and Applications of Fractional Differential Equations. North-Holland Mathematics Studies, Vol. 204, Elsevier Science B.V., Amsterdam.
4. Diethelm, K. (2010) The Analysis of Fractional Differential Equations: An Application-Oriented Exposition Using Differential Operators of Caputo Type. Springer, Berlin.
5. Positive solutions to singular boundary value problem for nonlinear fractional differential equation