GND ID
The Integrated Authority File (German: Gemeinsame Normdatei; also known as the Universal Authority File) or GND is an international authority file for the organisation of personal names, subject headings and corporate bodies from catalogues. It is used mainly for documentation in libraries and increasingly also by archives and museums. The GND is managed by the German National Library (German: Deutsche Nationalbibliothek; DNB) in cooperation with various regional library networks in German-speaking Europe and other partners (source).
Every entity in the GND features a unique and stable identifier (GND ID). This makes it possible to link the authority data with both each other and external data sets and web resources. This results in a cross-organisational, machine-readable data network (source)