1. Leibnitz, G.W.: Letter to G. A. L’Hospital. Leibnitzen Mathematishe Schriften 2, 301–302 (1849)
2. Liouville, J.: Sur le calcul des differentielles a indices quelconques. J. Ec. Polytech. 13, 71–162 (1832)
3. Riemann, B.: Versuch einer allgemeinen auffassung der integration and differentiation. In: Gesammelte Werke, vol. 62 (1876)
4. Atanackovic, T.M., Stankovic, B.: Generalized wave equation in nonlocal elasticity. Acta Mech. 208(1–2), 1–10 (2009)
5. Beyer, H., Kempfle, S.: Definition of physically consistent damping laws with fractional derivatives. ZAMM 75(8), 623–635 (1995)