Wiederkehr, Peter, Richard Gilbert, Philippe Crist, and Nadia Caïd. “Environmentally Sustainable Transport (EST): Concept, Goal, and Strategy – The OECD’s EST Project”. European Journal of Transport and Infrastructure Research 4, no. 1 (March 1, 2004). Accessed March 28, 2024. https://journals.open.tudelft.nl/ejtir/article/view/4254.