Open Access Repository of the Physikalisch-Technische Bundesanstalt (PTB-OAR)

PTB is the national metrology institute of the Federal Republic of Germany.
This database offers free access to numerous documents and factual data sets that were created at PTB. These include, for example, PTB-Mitteilungen, PTB's metrological journal and numerous documents from legal metrology.
When downloading the publications, please observe the stated license conditions for further use.