T. R. Elem, I. C. Ogwude, C. C. Ibe, K. U. Nnadi, and E. A. Ejem, “Decoupling of economic activity and freight transport volume: An evidence for short sea shipping future in the ECOWAS sub-region”, J. sustain. dev. transp. logist., vol. 5, no. 2, pp. 124–134, Nov. 2020.