The Open Transport Net project (OTN) has published the first white paper out of three focused on data harmonisation and interoperability in OTN. SDI4Apps collaborates with OTN on several data sets including the Open Transport Map described in the first white paper and Smart Points of Interest and Open Land Use Map, which will be described in the second white paper.
WHITE PAPER I: Data Harmonization & Interoperability in OpenTransportNet
This wait paper coming from OTN is useful also for SDI4Apps and FOODIE. I believe, that this is good document to demonstrate importance of different standardization efforts and also could help to community.