S. Carpintero and  R. Barcham,  PPP in Light Rail Transit Systems in Spain.   journal   = {International Journal of Humanities and Social Sciences}, [online]. World Academy of Science, Engineering and Technology.
    May 2012, vol. 65(5). 853 - 856
    [viewed 19 September 2024]. Available from: https://publications.waset.org/pdf/11028.