Public transport – Service interface for real-time information relating to public transport operations – Part 5: Functional service interfaces situation exchange: Situation Exchange; English version CEN/TS 15531-5:2016
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 07/01/2016

Public transport – Service interface for real-time information relating to public transport operations – Part 5: Functional service interfaces – Situation Exchange; English version CEN/TS 15531-5:2011
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 10/01/2011