C.A. Monje, B.M. Vinagre, Y.Q. Chen, V. Feliu, P. Lanusse, J. Sabatier. Optimal Tunings for Fractional PID Controllers, Fractional Differentiation and Its Applications. ISBN: 3-86608-026-3, Ubooks Verlag. pages: 675 - 686. . 2005.