1. Willis R. Experiments for determining the effects produced by causing weights to travel over bars with different velocities. In: Grey G et al., editors. Report of the Commissioners Appointed to Inquire into the Application of Iron to Railway Structures. London: W. Clowes; 1849
2. Stokes GG. Discussion of a differential equation relating to the breaking of railway bridges. Transaction Cambridge Philosophical Society. 1849;8(Part 5):707-735
3. Zimmerman H. Die Schwingungen eines Tragers mit bewegter Last. Centralblatt der Bauver waltung, Berlin. 1896;16(23):249-251, (23A):257-260, (24):264-266, (26):288
4. Krylov AN. Mathematical collection of papers of the. Academy of Sciences. 1905;61:211
5. Timoshenko SP. On the forced vibration of bridges. Philosophical Magazine. 1922;6(43):1018, 707-735