Sys, C., Vanelslander, T., Ponnekeblom, G., & Crius Group, H. (2011). Future challenges for inland navigation: A scientific appraisal of the consequences of possible strategic and economic developments up to 2030. University Press Antwerp.

Sys, Christa, Thierry Vanelslander, Gentbrugge Ponnekeblom, and Hulshout Crius Group. Future Challenges for Inland Navigation: A Scientific Appraisal of the Consequences of Possible Strategic and Economic Developments Up to 2030. Brussels, Belgium: University Press Antwerp, 2011.

Sys, Christa, et al. Future Challenges for Inland Navigation: A Scientific Appraisal of the Consequences of Possible Strategic and Economic Developments Up to 2030. University Press Antwerp, 2011.