1. Bendall, HB and Stent, AF . (2001): A scheduling model for a high speed containership service: a hub and spoke short-sea application. International Journal of Maritime Economics 3: 262–277.
2. Blauwens, G, Janssens, S, Vernimmen, B and Witlox, F . (2003): A logistical analysis of transport frequency. In: Dullaert, W (ed). Across the Border: Building Upon a Quarter Century of Transport Research in the Benelux. De Boeck: Antwerp. pp. 69–87.
3. Commission of the European Communities. (2001): White Paper on European Transport Policy for 2010: time to decide. COM(2001). 370, 12-09-2001, Brussels.
4. Coyle, JJ, Bardi, EJ and Langley Jr, CJ . (1996): The management of business logistics. 6th edn. West Publishing Company: Minneapolis, St Paul.
5. Directorate-General Energy and Transport. (2003): Statistical pocketbook 2003. European Union: Energy and Transport in Figures, Brussels. Most of the data cover the period 1970–2001.