1. Åström, K.J., Hagglund, T.: PID Controllers: {Theory, Design, and Tuning}, 2nd edn. Instrument Society of America, Research Triangle Park, NC (1995)
2. Axtel, M., Bise, E.M.: Fractional calculus applications in control systems. In: Proceedings of the IEEE 1990 National Aerospace and Electronics Conference, NY, pp. 563–566 (1990)
3. Caponetto, R., Fortuna, L., Porto, D.: Parameter tuning of a non-integer order PID controller. In: Proceedings of the 15th International Symposium on Mathematical Theory of Networks and Systems, University of Notre Dame, IN (2002)
4. Charef, A.C., Sun, H.H., Tsao, Y.Y., Onaral, B.: Fractal systems as represented by singularity function. IEEE Trans. Autom. Control 37(9), 1465–1470 (1992)
5. Chen, Y.Q., Moore, K.L., Vinagre, B.M., Podlubny, I.: Robust PID controller autotuning with a phase shaper. In: Le Mehauté, A., Tenreiro Machado, J.A., Trigeassou, J.C., Sabatier, J. (eds.) Fractional Derivatives and Their Applications, pp. 687–706. UBooks, Augsburg, Germany (2005)