1. 1. Marine insight. Retrieved from: https://www.marineinsight.com/. (in English).
2. 2. Nwaogbe, O. R., Nwuzor, O. A., Onyema, H. K., Evans, C., & Eru, J. (2020). An evaluation of port operations performance in Nigeria: Case of Calabar free port. The International Journal Transport & Logistics, 20(48), 60-72 (in English).
3. 3. Salawu, R. O., & Awolowo, O. (2009). The effect of capital structure on profitability: An empirical analysis of listed firms in Nigeria. The International Journal of Business and Finance Research, 3(2), 121-129. (in English).
4. 4. Offiong, V. E., Awoyemi, O. K., Maduka, F. O., Ewa, E. E., & Onogbosele, C. I. (2015). An assessment of touting activities in selected urban motor parks in Ibadan metropolis. Journal of Environment and Earth Science, 5(9), 170-178. (in English).
5. 5. Lazarus, O., & Ukpere, W. I. (2011). A strategic reposition of the maritime industry for economic recovery and sustainability: "The Cabotage Act". African Journal of Business Management, 5(14), 5658-5663. doi: 10.5897/AJBM10.1160 (in English).