معاونت دیپلماسی اقتصادی وزارت امور خارجه جمهوری اسلامی ایران
https://en.wikipedia.org/wiki/List_of_countries_by_road_network_size
https://www.citypopulation.de/en/world/bymap/Railways.html
https://en.wikipedia.org/wiki/Romania
https://en.wikipedia.org/wiki/List_of_countries_by_Internet_connection_speeds
https://www.citypopulation.de/en/world/bymap/InternetUsers.html
https://www.citypopulation.de/en/world/bymap/TelephoneLines.html
https://www.citypopulation.de/en/world/bymap/MobilePhones.html
https://en.wikipedia.org/wiki/List_of_countries_by_vehicles_per_capita
Access to electricity (% of population) | Data (worldbank.org)
www.iea.org