How to implement Persistent Identifier (PID)?

Hello, I tried to put down the Persistent Identifier (internet-adress) in the DOI-Field. But it doesn't work.The PID is: https://nbn-resolving.org/urn:nbn:de:0168-ssoar-67412-2 (I checked it -...

27 April 2020 4,113 0 View