Key Expert activities performed: Identified relevant primary and secondary legislation of regulatory authorities interacting with the National Single-Window system at the Customs Administration, collected, analysed and proposed modifications for harmonization with the new Law on National Single-Window System at the Customs Administration. The activities involved the Customs Administration, Ministry of Economy, Ministry of Interior, Radiation Safety Directorate, Ministry of Agriculture, Forestry and Water Management, State Agriculture Inspectorate, Ministry of Health, Agency for Medicines and Medical Devices, State Sanitary and Health Inspectorate, Food and Veterinary Agency, Ministry of Environment and Physical Planning and the Directorate for Protection of Cultural Heritage.