Rietveld, P., Dekkers, J. and van Woudenberg, S. 2002. Choice of Frequency and Vehicle Size in Rail Transport: Implications for Marginal External Costs. European Journal of Transport and Infrastructure Research. 2, 2/3 (Apr. 2002). DOI:https://doi.org/10.18757/ejtir.2002.2.2.3691.